All Cisco-Examinations

Ppp Connection With Chap

2009-04-30T17:18:00.000-07:00

Problem:

This is the problem: suppose two routers are connected using PPP with CHAP over a serial link. However, on one of the routers the command 'ppp authentication chap' has not been issued. Everything else is fine.

Now, some text says the link status should be 'line protocol is up'. NetSim shows 'line protocol is down'. Which one is it with real routers?

Solution #1:
Haven't tried it with real touters, but I did find this explanation on the net, and it makes sense:

"CHAP does not actually send the password over the line at all. Instead, CHAP runs a hash algorithm using the password and a random number. It is the result of this hash that is passed over the link. The remote router receives the hash result, and runs the exact same algorithm. If the result is the same, the authentication attempt will be successful. If the result is different, the authentication will fail. For this reason, the passwords must be the same.

Since two passwords are involved, the chances of one of the passwords being mistyped doubles. If you configure CHAP and the link dials but drops almost immediately, there's an authentication problem. Run debug ppp negotiation and attempt to dial the line again. The output of this particular debug will show you where the problem is. "
from

CODE

http://www.faqs.org/contrib/articles2/Introduction-To-ISDN-Part-IV-PPP-CHAP.html

You will find a very clear explanation in Sybex p. 532-533.
Results of a show interface when authentication fails:

"Pod1R1#sh int s0/0
Serial0/0 is up, line protocol is down
Hardware is PowerQUICC Serial
Internet address is 10.0.1.1/24
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 243/255, txload 1/255, rxload 1/255
Encapsulation PPP, loopback not set
Keepalive set (10 sec)
LCP Closed
Closed: IPCP, CDPCP

First, notice in the first line of output that serial0/0 is up, line protocol is down.
This is because there are no keepalives coming from the remote router. Next, notice that the LCP is closed because the authentication failed."Sybex p.533

Solution #2:
QUESTION NO: 7
Part of the configuration files for routers testknight1 and testknight2 are displayed
below:

hostname testknight1
username testknight2 password knight
interface serial 0
ip address 12.3.6.2 255.255.0.0
encapsulation ppp
clockrate 56000

hostname testknight2
username testknight1 password knight
interface serial 0
ip address 12.3.6.3 255.255.0.0
encapsulation ppp
ppp authentication chap

If you were to enter the “show interface serial 0” command on router testknight1,
which of the following will be displayed? (Choose two)
A. Serial 0 is down, line protocol is down
B. Serial 0 is up, line protocol is up
C. Open: IPCP, CDPCP
D. LCP closed
E. LCP open

Suggested answer is B and E

Now...

1.) Boson NetSim shows Serial 0 is up, line protocol is down
2.) p533 of Sybex 5th ed. shows Serial 0 is up, line protocol is down
3.) p627 of Richard Deals CCNA study guide shows Serial 0 is up, line protocol is down

In addition, LCP is shows as ACKRCVD in (1.) and (3.), and Closed in (2.)

IPCP and CDPCP show as closed in (1.) and (2.)

Looking at the cisco site http://www.cisco.com/warp/public/471/under...g_ppp_chap.html

One-Way and Two-Way Authentication
CHAP is defined as a one-way authentication method. However, you use CHAP in both directions to create a two-way authentication. Hence, with two-way CHAP, a separate three-way handshake is initiated by each side.

One-way authentication is often required when you connect to non-Cisco devices.

For one-way authentication, configure the ppp authentication chap callin command on the calling router.

Table 1 – When to Configure the Callin Option

Authentication Type________________Client (calling)_________________________NAS (called)
One-way (unidirectional)___________ppp authentication chap callin___________ppp authentication chap
Two-way (bidirectional)____________ppp authentication chap ppp______________authentication chap

So I guess from this, the question answers are wrong. Boson and the books are correct?

A. Serial 0 is down, line protocol is down => maybe should be Serial 0 is up, line protocol is down which would be correct

B. Serial 0 is up, line protocol is up - wrong

C. Open: IPCP, CDPCP - definately wrong

D. LCP closed - possibly correct (maybe Boson isn't showing accurate answer, after all its only a beta)

E. LCP open - definately wrong

Solution #3:
PPP session establishment has three phases:

1.Link establishment phase.
"Each PPP device sends LCP packets to configure and test the data link. LCP packets contain a Configuration Option field that allows devices negotiate the use of options (one of them is link authentication protocol).

2.Authentication phase (optional)
After the link has been established and the authentication protocol decided on, the peer may be authenticated. Authentication takes place BEFORE the network layer protocol phase.

3.Netwrk layer protocol phase
PPP sends NCP packets to choose and configure one or more network layer protocols"
from KNETICND

So let`s think...

Scenario 1
C. Open: IPCP, CDPCP - if it` open so the following statements are true too:
E. LCP open
B. Serial 0 is up, line protocol is up

Scenario 2
D. LCP closed if it`s closed so the link must be down
A. Serial 0 is down, line protocol is down ( i guess there is a typo as always in tk and it must be up-down)

IN our case (Q7)
The right answers are A D, I guess

Access List

2009-04-30T17:12:00.000-07:00

Problem:

Does anyone know the best way to remember access lists
how to use them effectively and do you need to know them real good for the ccna 640-801 exam

Solution #1:
I did 640-801 exam a few days ago. Of cause, there are some questions about ACL.
But you dont have to type them for CCNA. But you must know the useage and the synthax.
There is nothing to "remember". You have to understand the difference between standard and extended ACLs, know about best practice for placement of an ACL, and know the synthax of it.
You must understand the wildcard-calculation, but this is also dead simple!
Without knowledge of FAST Subnet and Wildcard Calculation you should NOT do the exam, dude!

access-list [optional eq ]

I dont want to explain to you all about acls. There is enough literature available.

They are easy, when you understand the concept.

1. Create some statements

access-list 100 deny tcp 154.55.64.0 0.0.0.255 143.55.6.7 0.0.0.0 eq 23
access-list 100 deny tcp 165.67.32.0 0.0.0.255 143.55.6.7 0.0.0.0 eq 23
access-list 100 permit ip any any

2. All the statements together build ONE Access List. That ACL can be binded on a interface

interface e0

ip access-group 100 in

The ACL in the example would deny telnet (23) access to host 143.55.6.7 from the networks 154.55.64.0 and 165.67.32.0.

Solution #2:
Do not forget access-class statements to limit users access, such as under "line vty 0 4"

Preventing Loops (dist-vector)

2009-04-30T16:56:00.000-07:00

p567 v81
QUESTION NO: 52

How does route poisoning work with holddown timers to prevent routing loops?
A. Information learned from one source is not distributed back to that source.
B. Routing updates from the poisoned source are ignored until a holddown timer expires.
C. Failed routes are advertised with infinite metrics.
D. New routing updates are ignored until the network has converged.
E. A route is marked as unavailable when its time-to-live is exceeded.

Answer: C

Answer is wrong coz
C Failed routes are advertised with infinite metrics -it`s route poisoning
B Routing updates from the poisoned source are ignored until a holddown timer expires - it`s route poisoning with holddown timers

Odom p154 ICND
Route poisoning—When a route to a subnet fails, the subnet is
advertised with an infinite-distance metric. This term
specifically applies to routes that are advertised when the
route is valid. Poison reverse refers to routes that normally are
not advertised because of split horizon but that are advertised
with an infinite metric when the route fails.

Hold-down timer—After finding out that a route to a subnet
has failed, a router waits a certain period of time before
believing any other routing information about that subnet.

Solution #1:
I think the answer is C.

B.Routing updates from the poisoned source are ignored until a holddown timer expires.

Its not B because if the source comes up, the router will jump the holdtime and install the route. Holdtime is used so that the destination unreachable message travels all across the network. And during the holdtime the router will avoid any messages on routes available for that destination, thinking that, it may be because of looping.

But once the source router, ( which may have had that particular link down, & later it would have come up), advertises the route to the destination, the holdtime is jumped and the route is installed.

"When a router detects a link failure between itself and a neighbor, it sends a flash update with a poisoned
route to it other neighbors. These neighbors in turn create a new flash update and send it to all of its
neighbors, and so on. The Router that detected the link failure purges the entry for the failed link and
removes all routes associated with that link from the routing table. The router then sends a query to its
neighbors for the routs that have been removed. If a neighbor responds with a route, it is immediately
installed in the routing table. The router does not go into hold-down because the entry was already purged.
However, its neighbors are in hold-down for the failed route, thus ignoring periodic advertisement for that
route. As the other routers come out of hold-down, the new route announced by the router that detected the
failed link will cause their routing table entries to be updated"

Solution #2:

QUOTE

Say r1 has a route to a destination X. Now things work fine. U have r2 connected to r1.So r2 knows through r1 the route to detination x is via r1 lets say a hop count of 2. now some link in that route r1---X fails.

So r1 will poison the route as unreachable. r2 will override the split horizon rule and poison reverse to r1...saying ok buddy, i got your info. And r2 will start its hold down timer.

Now say suppose another route exists to this destination X via r3 & its workiing fine , but the hop count is 4. when r3's advertisement to dest X is received by r2, r2, simply ignores it,....reason, r2 thinks that route which has a higher metric is because of loop.

That`s ok, you right.

"Now, say in the meantime, r1---x link comes up. r1 will advertise this route. r2 will immediately jump holdtime and associate the route......why?...reason. 1. since it has got the same hop count."

I dont understand the reason, really!
So the question asks How does route poisoning work with holddown timers to prevent routing loops?

Route poisoning=infinite metric out of all interfaces
Holddown=ignore ANY information about an alternative routes to poisoned network

So Route poisoning + Hold-down = updates about network with infinite metric are not valid until enough time passes so that everyone has heard the old, bad information.

So i guess "B. Routing updates from the poisoned source are ignored until a holddown timer expires."
is right.

Gambit Mimic Vs Netsim6, gambit mimic vs netsim6

2009-04-30T16:49:00.000-07:00

Problem:
hi i want to know abt gambit mimic virtual lab ccna 1.11

i hv it but idnt hv the license............i want to know that whether it is of any purpose fr ccna preparation........if it is then iwll try to get license other wise?
i hv already netsim6 beta 3b & netsim 5.27 routersim beta

wht u people say?

Solution #1:
With MIMIC Virtual Lab CCNA 1.50 you can disconnect/reconnect links.
In the next version you will be able to add/remove links between devices.
In a future version you will be able to substitute devices.

The trick is to support this and still work correctly. All of the other simulators out there
will allow you to change the network, but then fail miserably in the commands.

Check out the latest version at

CODE

http://www.gambitcomm.com/.

Solution #2:
MIMIC is useful for the thousands of people who buy it, and who want a reliable simulator.
Search for "mimic" in these forums to see who else passed their CCNA exam with its help.
That support lets us improve the product based on customer feedback.
What use is a simulator that lets you play with topologies, then fails in faithfully
executing the most basic commands, as is the norm out there?

The topology we provide in each of the simulators tries to cover what you need to
certify. The MIMIC Virtual Lab CCNA is for CCNA, the BSCI for BSCI, etc. The command
set is as complete and true as we can make it, covering side effects such as syslog,
SNMP objects and traps, etc. For example, the "copy" command will actually TFTP to/
from a server (and obviously fail if you haven't set it up correctly).The lab exercises are there
if you need hand-holding, but we also believe in letting you explore to your heart's content.

As far as active links, I'm sorry, I did not do anything special to make it active.
I did not know I had to do a special thing to make it inactive. I will try to edit the
previous post.

Solution #3:
MIMIC Virtual Lab CCNA supports ALL the commands necessary for CCNA certification,
and more, If by "do the configuration" you mean to change the topology, as explained before
you can currently only disconnect/reconnect links. Contrary to other simulators out there,
the command set is less buggy and more complete. Detailed info and a Flash demo is at our
website, as posted above.

In fact, MIMIC is good enough to be resold by Cisco Certified Partners, eg. check out
"http://www.t2000inc.com/CCNA_Labsim/" . Colleges are buying it in bulk for their training
courses, details at our site.

Switching Basix Question, ARP Request or what?

2009-04-30T16:40:00.000-07:00

Problem:
What does a Layer 2 switch do if it receives a frame with destination MAC address that is not found in its MAC address table?

A. The frame is dropped.
B. The frame is addressed with a broadcast MAC address and sent out all ports.
C. The frame is sent out all ports except the receiving port.
D. An ARP request is sent out all ports except the receiving port.
E. A destination unreachable message is sent back to the source address.
Answer:
Testking says C. I think i know that the Client will send out an Arp Request.
What do you think?

What does a Layer 2 switch use to decide where to forward a received frame?

A. source MAC address
B. source IP address
C. source switch port
D. destination IP address
E. destination port address
F. destination MAC address
Answer:
Testking says A, what is nonsense. It is F. What do you think?

Host from the 200.1.1.0 subnetwork cannot access a server located on the 200.1.1.64 subnetwork. The users have previously been able to access this server. After router Testking1 is accessed with the use of Telnet,
which of the following commands would be a logical first choice in troubleshooting this problem?

A. Testking1# show interface s0/0
B. Testking1# show controllers
C. Testking1# show ip route
D. Testking1# show hosts

Testking says C. But I would first look if the interface is shutdown, so i would take A. What do you think?

Solution #1:
[QUOTE]What does a Layer 2 switch do if it receives a frame with destination MAC address that is not found in its MAC address table?
[/QUOTE]

C. The frame is sent out all ports except the receiving port.

c is correct ...........
basically arp is alayer three protocol ...........(only for ip to macaddress mapping)
here switch is not able to eliver the packete directly to host bcoz switch dosen,t knoe that on whic port this destination macaddress is present........
so switch hv to get this informatioin first..........for this he ask every port tht whether there macaddress is this one..........(but switch dosen,t ask from sorce port bcoz switch knows it mac address and there is no chance tht destination address to be on same source port ) so switch broadcast this packet to all ports except the one on which he recived............

[/QUOTE]
What does a Layer 2 switch use to decide where to forward a received frame[QUOTE]

f is coorect ...a is 101% wrong

Solution #2:
Q1-right answer C

Odom ICND p13:
"Bridges forward LAN broadcast frames, and unknown unicast frames, out all ports. LAN broadcasts, by definition, are received by all devices on the same LAN. So the switch simply forwards broadcasts out all ports, except the one on which the broadcast was received. Switches forward unknown unicast frames, which are frames whose destination MAC addresses are not yet in the bridging table, out all ports as well. The switch floods the frame with the hope that the unknown device will be on some other Ethernet segment, it will reply, and the switch will build a correct entry in the address tab

Solution #3:
Q2- right answer A

Odom ICND p11
"Forwarding or filtering—The switch decides when to forward a frame or when to filter (not forward) it based on the destination MAC address. The switch looks at the previously learned MAC addresses in an address table to decide where to forward the frames."

"Learning—The switch learns MAC addresses by examining the source MAC address of each frame the bridge receives. By learning, the switch can make good forwarding choices in the future."

The difference is between WHEN and WHERE

Solution #4
Back to this question I would like to clarify.

QUOTE

Host from the 200.1.1.0 subnetwork cannot access a server located on the 200.1.1.64 subnetwork. The users have previously been able to access this server. After router Testking1 is accessed with the use of Telnet,
which of the following commands would be a logical first choice in troubleshooting this problem?

A. Testking1# show interface s0/0
B. Testking1# show controllers
C. Testking1# show ip route
D. Testking1# show hosts

The most of us and me too thought first that show interface s0/0 is the best choice.
BUT

What do u think about this

"If you have HDLC or PPP configured on your serial interface but your IP addresses are
not correct, this is a hard problem to see, since the interfaces will show up.
The two routers are connected with different subnets, router Pod1R1 with 10.0.1.1/24
and router Pod1R2 with 10.2.1.2/24. This will never work. However, take a look at
the output:

Pod1R1#sh int s0/0

Serial0/0 is up, line protocol is up
Hardware is PowerQUICC Serial
Internet address is 10.0.1.1/24
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, loopback not set
Keepalive set (10 sec)
LCP Open
Open: IPCP, CDPCP
Wow, check that out! The IP addresses are wrong between the routers, and the link looks like
it is working fine. This is because PPP, like HDLC and Frame Relay, is a layer 2 WAN encap-
sulation and doesn’t care about IP addresses. So yes, the link is up; however, you cannot use IP
across this link since it is misconfigured."

sybex p535

So the right answer is C

Why Vlans?

2009-04-30T15:51:00.000-07:00

Problem:
i created a network with 1 switch , and 12 hosts using routersim, then i configured 3 networks 192.168.1.x, 192.168.2.x and 192.168.3.x (masks:255.255.255.0) with ipaddresses on on the hosts. Then i tried to ping a host in 3.x network with another host in 3.x network (And it worked !!); Now i tried to ping a host in 1.x network from a host in 3.x network (and it failed!!). So........ did i create 3 broadcast domains?? if i did then why do we need VLANs?

Solution #1
no you didnt create 3 broadcast domains. Remember: Only a router or Vlans can seperate broadcast domains.

The hosts are in different subnets. You need a router to make communication between the subnets possible.

Solution #2
I think the point here is that yes you can use a switch to either

create seperate vlans and seperate broadcast domains

create multiple networks on the same switch - but in this case I think I'm correct in saying that a broadcast from a machine in one subnet on the switch will be sent to all ports of the switch, so will impact on all machines on the switch

However, when it comes to connecting these seperate networks with the first option you can use a single router port (using switchport mode trunk on the switch and a router on a stick - using subinterfaces BUT only one physical interfase.

The second option would i believe require a router port required for each network on the switch,

So the benefit of VLans here is

- true seperation of broadcast domains
- single router port for routing for a large number of networks

Solution #3
If I'm reading it right,

======----

where --- is one connection and === is two+ connections (one per subnet), then

I would guess you would have a single broadcast domain that covers both switches, and you would have a busy === connection, sicne all traffic would hit this, (not jsut the routed traffic as would be the case in a vlan trunk), but I could be wrong

Remember switched networks break up collision but not broadcast domains. It doesn't matter what IP addresses are on hosts connected to the switch, the switch is making decisions at layer 2 not layer 3, so a switch will always flood broadcasts to every port - as far as I'm aware anyway.

The only time this will not be the case is if ports are assigned to different vlans, in which case broadcatss are only flooded to ports in the same vlan

Depends - broadcast domains are seperated by routers and by vlans,

so if the traffic from the system making the broadcast has to pass through a router (using a subinterface) then the broadcast traffic will be stopped

e.g. pc ---------- switch ----------router subinterface <- nothing gets past here But pc1 ---------- switch port1 ----------|router subinterface <- nothing gets past here pc2 ---------- switch port2 ----------| if pc1 and pc2 need to use the subinterface to talk (diff subnets), then broadcatss are still only stopped where shown Solution #4
As your configuration,

- you have three subnets, you can not connect together because of different subnets
- you worry about broadcast domain, yes it is, but no collision domain due to you connect all your things to the switch (1 port, 1 host)

My solution for you:

If you want all subnets together, connect together via that SW, you need a layer 3 device, eg: router (simple case) along with a SW to do InterVLAN routing
(or: Router On Stick case)
- With router, you must have at least the router 2600 (eg: 2610, Ethernet 10Mb) that supported encapsulation dot1q (802.1q) to implement trunking to the SW
- SW: at least 2950, support dot1q

-> Using 1 link Router to SW, set trunk on that with dot1q encapsulation
-> Set on SW each subnet with equivalent VLAN, set ports to VLANs
-> Set each sub-interface with equivalent VLAN, set IP add for each sub-interface

- PCs: set IP, default GW(point to sub-ints on router) are suitable to each subnet

Then you can ping together

Solution #5
I hope i did get you right...

You have ONE Switch. And on that Switch are 12 hosts, on every Port one host.
And the hosts have IPs which are in different Subnets.

Of cause on each port will come broadcast pakets. All the Switchports are still in ONE broadcast domain.
But they will not be able to communicate together, as long as their ip-addresses are not in the same subnet.

If you want on the Switch for example Port 1 to be in one broadcast domain, and port 2 in another broadcast domain, you must create and name vlans for both of them and put the ports in the specified vlan with the command
(config)#vlan 3
(config-vlan)#name first_broadcast_domain
exit
(config)#vlan 2
(config-vlan)#name second_broadcast_domain
(config-vlan)#exit

So, vlans 3 and 2 are created.
Now lets bind switchports to different vlans

(config)#interface fa0/1
(config-if)#switchport mode access
(config-if)#switchport access vlan 2
(config-if)#no shutdown

(config)#interface fa0/2
(config-if)#switchport mode access
(config-if)#switchport access vlan 3
(config-if)#no shutdown

So, now there are seperated broadcast domains on ONE physical Switch.

But - if you want to route between this two different vlans, you need a router.
The router-port on which this switch is connected must be configured with subinterfaces (when ists a Cisco Router...), and it must be a trunkport. Also the Uplinkport on the Switch must be configured as Trunkport. The only function of trunkports (or the reason why they exist) - they are like "Bridges" that carry pakets with different vlan-ids across an uplink. Without trunks, it is not able for the device to seperate the vlans. Without trunks, only ONE vlan-type or id can cross the uplink.

switch(config)#interface fa0/24
switch(config-if)#description uplinkport to router
switch(config-if)#switchport mode trunk
switch(config-if)#no shutdown

How do we configure the binding of a special Network or Subnet to THAT VLAN?
VLANs dont care about Networks! They work only on OSI-Layer 2.
We simply give the subinterface of the Router which is attached to THAT VLAN an IP-Address. That will be the default Gateway for that specific VLAN.
The Hosts which are connected to switchports that are in that VLAN MUST be given IP-Addresses of THAT specific Subnet or Network. Thats all.

The native VLAN means, the pakets which pass THAT port, will not be tagged. It will be normal Ethernetpakets like on a switch without any VLANs.
The Trunkport on the Routes side, must ALSO have the vlan1 as native vlan, or it will not work in thousand years.

And of cause, you have to add the right Route on the Router, so that packets can come from Vlan 1 to Vlan 2.

VLANs are needed, if you want to span a broadcast domain (or call it subnet) over multiple switches or either many different routers. You cant achieve this without VLANs. Without VLANs, on ONE Routerport and the connected Switch and Uplink-Switches will be ONE Subnet. And on the next Routerport another Subnet. But you will not be able to bring a Port of a Switch that is connected to another Routerinterface into the same subnet as another switch hosts, which is connected to another routerinterface.

Vlan Configuration Advices Needed

2009-04-30T15:36:00.000-07:00

Problem :
Company A with VLAN_A and VLAN_B connected in their office, the switch connect to a router.

Company B ALSO have VLAN_A and VLAN_B connected in their office, the switch connect to a router.

IF i want to connect both company A and B together, to allowed the VLAN_A user in company A able to ping to VLAN_A in company B. what should i do?

i've setup a simulation environment in my netsim,
but seem it cannot be done.

WHAT I DID is....

1.) create VLAN.
2.) Assign port to each VLAN
3.) Setup VTP in same domain for both switches.
4.) Setup trunk port in both switch to router.
5.) hook up router in both end of the switch.
6.) setup sub-interface for each port which connected to the switch. and the IP address for the subinterface was VLAN's gateway address.
7.) Gateway of the PC in VLAN will point to the IP which i assigned to the router's subinterface.

it WON'T work. the pc in companyA VLAN_A cannot ping to VLAN A in company A,
NOT even the switch or router in Company A.

the connection in between router of Company A and company B is using another set of subnet address....

Company A
VLAN A (190.168.10.0/24) F0/1
VLAN B (172.16.1.0/24) F0/2
Switch F0/1 to VLAN A / F0/2 to VLAN B.
Switch trunk port at f0/12 Connect to Router E0
Router E0.0 no ip address/no shut
Router E0.1 192.168.10.1
Router E0.2 172.16.1.1
Router S0 192.168.20.5

Company B
VLAN A (190.168.10.0/24) F0/1
VLAN B (172.16.1.0/24) F0/2
Switch F0/1 to VLAN A / F0/2 to VLAN B.
Switch trunk port at f0/12 Connect to Router E0
Router E0.0 no ip address/no shut
Router E0.1 192.168.10.1
Router E0.2 172.16.1.1
Router S0 192.168.20.6

Solution #1
Why not trunk Company A Switch with Company B Switch and setup ISL on each end.
Make one switch the server and the other a client in the same domain.

Solution #2
It's ATM so it's packet switched (or cell switched) but it's not DDR, it's always available so it's like a leased line...but it's not a dedicated circuit since it's ATM.

We don't use VTP, we just define our VLANs manually at each location. VTP should work though, I don't see why not, we do get broadcasts across the ATM - it's a flat network - i.e. there are some servers at Head Office that are on the same subnet as workstations here - even though it's hundreds of miles away.

Should work on FR too with the broadcast directive.

Solution #3

QUOTE

you are not talking of a working environment mate. you are talking of an imaginary environment, as far as VLAN ing is concerned.

This must be a made up environment as in a real life WAN situation and you were using frame-relay your core layer would be using Catalyst Switches.

Routing on a stick is outdated (I know it is still being used)

But for the CCNA, CCNP & CCIE it is not required.

What is CCNA?

2009-04-30T06:41:00.000-07:00

Well the official definition is:

CODE

Cisco Certified Network Associate (CCNA®) validates the ability to install, configure, operate, and troubleshoot medium-size route and switched networks, including implementation and verification of connections to remote sites in a WAN.

Whats in it?

CODE

CCNA curriculum includes basic mitigation of security threats, introduction to wireless networking concepts and terminology and performance-based skills. This new curriculum also includes (but is not limited to) the use of these protocols: IP, Enhanced Interior Gateway Routing Protocol (EIGRP), Serial Line Interface Protocol Frame Relay, Routing Information Protocol Version 2 (RIPv2),VLANs, Ethernet, access control lists (ACLs).

When i read this i was like wow things have changed a lot. I gave my CCNA about three years ago, and it was nothing like this. Don't get me wrong it was hard as hell, but was more routing & switching. Now in the new CCNA R&S, you have wireless and a hint of security.

CCNA Exam info:

You can get your CCNA by either:

1) Passing one exam 640-802. Its close to 90 minutes long and have about 55-60 questions.

or

2) You can divide the course work into two parts.

i. 640-822 ICND1 : 90 minutes with 40-50 questions.
ii. 640-816 ICND2 : 90 minutes with 40-50 questions.

Whichever style of studying you decide to do the course work is the same.

Speaking of course work lets see whats in it:

a) Describe how a network works:

It always comes down to basics. The OSI model, the Hex, Asci, Dec conversions. The components of a network. The cables the devices and the types of networks. This is your foundation. Give as much time as you can to this.

b.) Configure, verify and troubleshoot a switch with VLANs and interswitch communications

The magic word is VLANs. Give as much time as you possibly can to understand how they work, and how to configure them. You will also want to learn how to configure a switch and how to do basic port security.

c) Implement an IP addressing scheme and IP Services to meet network requirements in a medium-size Enterprise branch office network

Its all about how to effectively deploy a network. Read about different IP classes. The most important thing is to know how to use subnetting to achieve a design goal. Practice, practice and practice. That the only way to learn it, learn it until its second nature to you.

You also want to learn about DNS and DHCP. In the new course work you are required to learn about IPV6 also. So give special attention to this. They will test you on this.

d) Configure, verify, and troubleshoot basic router operation and routing on Cisco devices

Here is where all the dirty work is done. You are required to learn about different routing protocols including RIP, EIGRP, IGRP and OSPF. You would want to learn about how to configure these routing protocols. Also pay special attention to the different Show and Debug commands.

You will also learn about the IOS, how it works, how to upgrade, copy and erase the configurations.

e) Explain and select the appropriate administrative tasks required for a WLAN

This is a new edition to the CCNA curriculum. It is very basic but still requires understanding of WLAN technologies, components and security options. Read and understand key terms like SSID, BSS, ESS, WEP and WPA.

f) Implement, verify, and troubleshoot NAT and ACLs in a medium-size Enterprise branch office network

You are required to have a deep understanding of how to configure and troubleshoot NAT.

Also securing your network with access lists is a major part of the CCNA curriculum. You will be asked to describe how the ACLs work. You may also be required to configure ACLs. Its very important that you understand different types of access-lists and how to apply them to the correct interfaces to achieve the design goals.

g) Implement and verify WAN links

For your CCNA, frame-relay is the next very important technology for you to understand. Give extra time to understanding how different WAN technologies work and how to configure them to achieve connectivity between remote devices, these will include PPP, Frame Relay and VPNs.

How to Study for it?

Its all upto to you. You don't have to start with a Cisco Official book if you don't want too. If you are new to networking, i would recommend you get some basic networking knowledge first. Use google if you have to, pickup a good networking book and read it.

Once you have a good understanding proceed to the official guides. If you can't afford one, use google, you will be amazed of how much information is out there.

Next you will need hands on experience with different cisco devices. The ideal solution would be to get some routers and switches, but if you can't afford to buy them then use simulation softwares.

I would recommend to either go with Cisco Packet Tracer or use GNS3. The difference is that you would be using real IOSs to emulate devices in GNS3.

I hope this little introduction to CCNA was helpful. Best of luck to all who are preparing for their CCNA. And remember if you have a problem, feel free to post it here.

CCNA PDF FILES

2009-04-28T05:25:00.000-07:00

 CCNA Examination
 CCNA Exploration
 CCNA ds_0905.indd
 The New CCNA Concentrations
 ICND1, ICND2, and CCNA Prep Lab Topology
 CCNA DS.qxd (Page 1)
 Draft CCNA 3
 CCNA-Security Flyer
 CCNA Boot Camp
 Gambit's MIMIC� Virtual Lab Simplifies CCNA� home study course
 MIMIC Virtual Lab CCNA
 Frequently Asked Questions: New CCNA Curricula
 Networking-Cisco CCNA Technical Certificate Major Code 62387
 Cisco CCNA Exam #640-507 Certification Guide
 CISCO CERTIFIED NETWORK ASSOCIATE (CCNA)
 Cisco Networking Academy Program
 Cisco Certified Networking Associate (CCNA) Course
 CCNA Timetable (Tue/Thu evenings), September 2008 start*
 CCNA REGISTRATION FORM
 Why should I Join CCNA at CISCO Regional Academy, CEG ?
 Cisco Regional Academy
 Cisco Networking Academy Program
 CONTINUING EDUCATION & DISTANCE LEARNING
 Cisco Press CCNA Value Packs Save your students 10%
 The CCNA Examination
 CCNA Application Form.xls
 Cisco Certified Network Associate (CCNA)
 CCNA 4: WAN Technologies
 CCNA 2: Router and Routing Basics
 Scope and Sequence: C C  N A E x pl or  at i on v 4 . 0
 ADMISSION NOTICE
 CCNA 1: Networking Basics
 CCNA 3: Switching Basics and Intermediate  Routing
 Success of the CCNA Program:
 CCNA Candidate Handbook
 CCNA / CCSP
 Cisco launches 3 new CCNA � CCNA Security � CCNA Voice � CCNA ...
 CCNA Essentials
 Cisco CCNA Certification Fast Track Programme
 Cisco Networking Academy CCNA Semester 3
 CCNA : Cisco Certified Network Associate Study Guide, 5th Edition ...
 Detecting Wireless LAN MAC Address Spoofing Joshua Wright, GCIH ...
 Cisco� CCNA� Networking
 CISCO CCNA COURSE �600.00
 Scope and Sequence: CCNA Exploration v4.0
 Cisco Boot Camp for CCNA Certification
 Western Australian Information Document 01 CISCO CERTIFIED NETWORK ...
 Cisco networking (CCNA)
 Increase Your Networking Knowledge CCNA Certification is the First ...
 ITCC 2408 � CCNA  3: LAN Switching and Wireless Spring 2009 ITCC ...
 CCNA Exploration: LAN Switching and Wireless Student Skills-based ...

Basic PIX Configuration

2009-02-07T18:42:00.000-08:00

Everyone needs a good, basic PIX Firewall configuration on-hand from time to time. Here is one I set up for a client that does the following:

1. NAT overload from an inside network to an outside network
2. Accept incoming PPTP VPN connections from ouside clients
3. Turns on the web-based GUI on the PIX

: Saved
:
PIX Version 6.3(4)
interface ethernet0 auto
interface ethernet1 100full
:These two lines activate the outside (Ethernet0) and inside (Ethernet1) interfaces
nameif ethernet0 outside security0
nameif ethernet1 inside security100
:These two lines assign names to the interfaces
enable password ------ encrypted
:Sets the password for privileged mode
passwd -------- encrypted
:Sets the telnet password
hostname pixfirewall
domain-name ciscopix.com
fixup protocol dns maximum-length 512
fixup protocol ftp 21
fixup protocol h323 h225 1720
fixup protocol h323 ras 1718-1719
fixup protocol http 80
fixup protocol rsh 514
fixup protocol rtsp 554
fixup protocol sip 5060
fixup protocol sip udp 5060
fixup protocol skinny 2000
no fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol tftp 69
:Fixup protocols allow advanced applications to work through NAT. All the above fixup protocol configuration is in the PIX by default.
names
access-list 101 permit ip 192.168.1.0 255.255.255.0 192.168.2.0 255.255.255.0
access-list 102 permit icmp any any
access-list 102 permit ip 192.168.2.0 255.255.255.0 192.168.1.0 255.255.255.0
access-list 103 permit ip any any
:Same access-list syntax as a router. These are used below.
pager lines 24
mtu outside 1500
mtu inside 1500
ip address outside x.x.x.x 255.255.255.248
:Sets the outside interface IP address
ip address inside 192.168.1.1 255.255.255.0
:Sets the inside interface IP address
ip audit info action alarm
ip audit attack action alarm
ip local pool pptp-pool 192.168.2.10-192.168.2.50
:Defines a local DHCP pool of addresses for the PIX to give to incoming PPTP VPN clients
pdm logging informational 100
pdm history enable
:This tracks access to the PDM (the web-based GUI) built-in to the PIX
arp timeout 14400
global (outside) 1 interface
:This is a HUGE command. It turns on NAT translation for all addresses matching NAT rule 1 (shown below) to be translated through the outside interface (to the Internet, in this case)
nat (inside) 0 access-list 101
:This creates NAT rule 0 which tells NAT not to translate addresses that are defined in access list 101 (shown above). This keeps NAT from translating any communication between internal clients (192.168.1.0/24) and VPN clients (192.168.2.0/24).
nat (inside) 1 0.0.0.0 0.0.0.0 0 0
:This creates NAT rule 1 which matches ALL addresses coming from the inside interface
conduit permit icmp any any
:Conduits are the old form of access-lists. This one permits all ICMP messages to the PIX
route outside 0.0.0.0 0.0.0.0 x.x.x.x
:Sets a default route to the ISP router (represented with x.x.x.x)
timeout xlate 0:05:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:00
timeout h323 0:05:00 mgcp 0:05:00 sip 0:30:00 sip_media 0:02:00
timeout uauth 0:05:00 absolute
aaa-server TACACS+ protocol tacacs+
aaa-server TACACS+ max-failed-attempts 3
aaa-server TACACS+ deadtime 10
aaa-server RADIUS protocol radius
aaa-server RADIUS max-failed-attempts 3
aaa-server RADIUS deadtime 10
aaa-server LOCAL protocol local
http server enable
http 192.168.1.0 255.255.255.0 inside
:Turns on the HTTP interface to the PIX, but only allows internal users (192.168.1.0/24) to access it. This enables the PDM (the web-based GUI) on the PIX
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
sysopt connection permit-pptp
:Also a very huge command. This allows PPTP connections to the PIX firewall without the need for an access-list permitting PPTP. You can also use commands like sysopt connection permit-ipsec to permit IPSEC VPN connections
telnet 192.168.1.0 255.255.255.0 inside
:Allows telnet access to the PIX only from the internal subnet
telnet timeout 5
ssh timeout 5
console timeout 0
vpdn group 1 accept dialin pptp
:Allows PIX to accept PPTP connections
vpdn group 1 ppp authentication pap
vpdn group 1 ppp authentication chap
vpdn group 1 ppp authentication mschap
:Allows PPTP users to authenticate using any of the above methods (listed from weakest to strongest)
vpdn group 1 ppp encryption mppe auto
vpdn group 1 client configuration address local pptp-pool
:Points the PIX to hand out IP addresses to incoming VPN clients from the DHCP pool called "pptp-pool" (shown above in the config)
vpdn group 1 client configuration dns 192.168.1.252
vpdn group 1 client configuration wins 192.168.1.251
:Points the VPN clients to the right DNS and WINS server addresses
vpdn group 1 pptp echo 60
:Sends an "echo" (kinda like a keepalive) once every 60 seconds. If a response is not heard, VPN is torn down
vpdn group 1 client authentication local
:Authenticates VPN users using a local user database (shown below)
vpdn username jonesr password *********
vpdn username cepa password *********
vpdn username bob password *********
:Three VPN users allowed to connect
vpdn enable outside
:Turns on VPN connectivity on the outside interface
dhcpd lease 3600
dhcpd ping_timeout 750
username cisco password -------- encrypted privilege 15
:If I telnet with this username/password, I go straight to privileged mode
terminal width 80
: end

from JC

VPN Virtual Tunnel Interfaces

2009-02-07T18:40:00.000-08:00

While doing a recent deployment, I ran across this concept. It's a slightly different way to configure VPNs on a Cisco router that (for me) is far less confusing and finicky. If you've ever configured VPNs using a PIX firewall or IOS router, you probably know of the pain associated with making sure your crypto map is correctly configured. There are SO MANY pieces of it, you're almost assured that something is not going to match between one side of the connection and the other (especially that "interesting traffic" ACL). That's where these IPSec Virtual Tunnel Interfaces come in. Check this out...

Instead of configuring crypto maps between your routers, you create virtual interfaces. So the VPN has it's own "point-to-point" style connection between sites. The best way to get this is to see a configuration example. I borrowed the syntax / graphic for this example from Richard Deal's Complete Cisco VPN Configuration Guide by Cisco Press (awesome book, by the way).

RouterA Configuration:
RTRA(config)# crypto isakmp policy 10
RTRA(config-isakmp)# encryption aes 128
RTRA(config-isakmp)# hash sha
RTRA(config-isakmp)# authentication pre-share
RTRA(config-isakmp)# group 2
RTRA(config-isakmp)# exit
RTRA(config)# crypto isakmp key cisco123 address 193.1.1.1 255.255.255.255 no-xauth
RTRA(config)# crypto ipsec transform-set RTRtran esp-aes esp-sha-hmac
RTRA(cfg-crypto-trans)# exit
RTRA(config)# crypto ipsec profile VTI
RTRA(ipsec-profile)# set transform-set RTRtran
RTRA(ipsec-profile)# exit
RTRA(config)# interface tunnel 0
RTRA(config-if)# ip address 192.168.3.1 255.255.255.0
RTRA(config-if)# tunnel source 192.1.1.1
RTRA(config-if)# tunnel destination 193.1.1.1
RTRA(config-if)# tunnel mode ipsec ipv4
RTRA(config-if)# tunnel protection ipsec VTI
RTRA(config)# interface Ethernet0/0
RTRA(config-if)# ip address 192.1.1.1 255.255.255.0
RTRA(config-if)# exit
RTRA(config)# interface Ethernet 1/0
RTRA(config-if)# ip address 192.168.1.1 255.255.255.0
RTRA(config-if)# exit
RTRA(config)# ip route 192.168.2.0 255.255.255.0 tunnel0

RouterB Configuration:
RTRB(config)# crypto isakmp policy 10
RTRB(config-isakmp)# encryption aes 128
RTRB(config-isakmp)# hash sha
RTRB(config-isakmp)# authentication pre-share
RTRB(config-isakmp)# group 2
RTRB(config-isakmp)# exit
RTRB(config)# crypto isakmp key cisco123 address 192.1.1.1 255.255.255.255 no-xauth
RTRB(config)# crypto ipsec transform-set RTRtran esp-aes esp-sha-hmac
RTRB(cfg-crypto-trans)# exit
RTRB(config)# crypto ipsec profile VTI
RTRB(ipsec-profile)# set transform-set RTRtran
RTRB(ipsec-profile)# exit
RTRB(config)# interface tunnel 0
RTRB(config-if)# ip address 192.168.3.2 255.255.255.0
RTRB(config-if)# tunnel source 193.1.1.1
RTRB(config-if)# tunnel destination 192.1.1.1
RTRB(config-if)# tunnel mode ipsec ipv4
RTRB(config-if)# tunnel protection ipsec VTI
RTRB(config)# interface Ethernet0/0
RTRB(config-if)# ip address 193.1.1.1 255.255.255.0
RTRB(config-if)# exit
RTRB(config)# interface Ethernet 1/0
RTRB(config-if)# ip address 192.168.2.1 255.255.255.0
RTRB(config-if)# exit
RTRB(config)# ip route 192.168.1.0 255.255.255.0 tunnel0

The configuration is pretty straightforward, especially if you've configured GRE tunnels before. The difference is you use the "tunnel mode ipsec ipv4" command to notify the router that this is an IPSec-based interface rather than GRE and the "tunnel protection ipsec " command to choose the type of encryption (transform-set) for the interface.

The best part of the whole thing is NO CRYPTO MAPS!!! :) I love it - traffic is associated with a remote site using "ip route" static routes rather than mirrored ACLs. Awesome stuff!

Ideal CCNA Lab Setup

2009-02-07T18:36:00.001-08:00

Many of my CCNA-desiring friends have asked me if I could create a post that shows the ideal budget-conscious "study-lab" to prepare for the CCNA exam. Here's my suggestion:

The minimal equipment that I would purchase for the lab is as follows:

Here's the breakdown (prices updated 5.2008):

-Cisco 2514 router (two serial / two ethernet) with 16Mb Flash and 16Mb Ram ($20.00 - $45.00 Ebay price)
-Cisco 2900XL switch ($20.00 - $40.00 Ebay price); 1912 if your really budgetting ($5.00 - $15.00 Ebay price)
-Cisco 2501 router (two serial / one ethernet) with 16Mb Flash and 16Mb Ram ($15.00 - $35.00 Ebay price)
-Crossover serial cable ($5.00 - $20.00 Ebay price)

While this configuration is not the ideal, it will allow you to practice just about any CCNA-level concept you'd like. I'd recommend configuring it just as shown in the diagram (route your Cable/DSL home connection through the 2514) so you can practice NAT. The price differences for the equipment depends on your Ebay savvy-ness.

My recommended setup is just *slightly* more expensive (okay, maybe a little more than slightly), but will allow you to have 100Mbps connectivity to test inter-vlan routing configurations:

-Cisco 2621 router (two fast ethernet ports) with 16Mb Flash and 32Mb Ram ($150.00 - $250.00 Ebay price)
-Cisco 2900XL switch ($20.00 - $40.00 Ebay price)
-Cisco 1721 router (one fast ethernet) with 16Mb Flash and 32Mb Ram ($55.00 - $75.00 Ebay price)
-Crossover serial cable ($5.00 - $20.00 Ebay price)
-Two WIC-1T Serial modules for the routers ($25.00 - $75.00 Ebay Price)

This setup will allow you to move into the CCNP track with ease. Hope this helps!!!

from JC

IP SLA Sample Configuration for Voice

2009-02-07T18:34:00.001-08:00

IP SLA has the ability to measure "real-time" WAN connection quality. You can then use the results of the measurement for routing decisions (such as choosing an alternate path). This is especially effective for VoIP connections. The following sample configuration can be used to create a IP SLA Jitter/Packet Loss monitor for use with VoIP deployments:

IP SLA Source

Source(config)#ip sla 100 !Some IOS versions use ip sla monitor
Source(config-ip-sla)#udp-jitter 172.16.1.2 65424 codec g729a
Source(config-ip-sla-jitter)#tos 176 !Marks packets with DSCP EF (IP Precedence 5)
Source(config-ip-sla-jitter)#exit
Source(config)#ip sla schedule 100 recurring start-time now
Source(config)#interface s0/1/0
Source(config-if)#ip address 172.16.1.1 255.255.255.0

IP SLA Responder

Responder(config)#ip sla responder !Some IOS versions use ip sla monitor
Responder(config)#interface s0/1
Responder(config-if)#ip address 172.16.1.2 255.255.255.0

Configuring (simple) SNMPv3

2009-02-07T18:31:00.000-08:00

SNMP is awesome...All the free SNMP utilities for Cisco devices are even more awesome...but the most popular versions of SNMP (Version 1 and 2c) are completely clear text, completely insecure. SNMPv3 adds authentication and encryption capabilities, however, GOOD LUCK finding an easy, working configuration on Cisco's website. Here's an SNMPv3 configuration that will provide both authentication and encryption services on Cisco routers and switches:

Router(config)#snmp-server group TESTGROUP v3 priv
Router(config)#snmp-server user Jeremy TESTGROUP v3 auth sha JeremyPassword priv des56 3NCRYPT!0NK3Y

*Note: "auth" methods support both md5 and sha
**Note: "priv" also allows AES encryption
***Note: Most SNMP utilities I've seen only support DES encryption

Automatic Err-Disable Recovery

2009-02-07T18:30:00.000-08:00

Someone showed me a great feature today. One of the constant pains in the network is when you get a port err-disabled on the switch. Regardless of how many times I see it, it always seems to be the last thing I check. There's a little-known feature in the IOS called "err-disable recovery" which automatically turns a err-disabled switchport back on after 5 minutes (by default). The good news is that this command allows you to choose specific reasons where you'd like to re-enable the port, such as re-enabling ports disabled because of a port-flap instance but keeping mac-address security violations error disabled. Here's the syntax to make it happen:


CAT3550#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
CAT3550(config)#errdisable recovery ?
 cause     Enable error disable recovery for application
 interval  Error disable recovery timer value
CAT3550(config)#errdisable recovery cause ?
 all                   Enable timer to recover from all error causes
 arp-inspection        Enable timer to recover from arp inspection error
                       disable state
 bpduguard             Enable timer to recover from BPDU Guard error
 channel-misconfig     Enable timer to recover from channel misconfig error
 dhcp-rate-limit       Enable timer to recover from dhcp-rate-limit error
 dtp-flap              Enable timer to recover from dtp-flap error
 gbic-invalid          Enable timer to recover from invalid GBIC error
 inline-power          Enable timer to recover from inline-power error
 l2ptguard             Enable timer to recover from l2protocol-tunnel error
 link-flap             Enable timer to recover from link-flap error
 link-monitor-failure  Enable timer to recover from link monitoring failure
 loopback              Enable timer to recover from loopback error
 mac-limit             Enable timer to recover from mac limit disable state
 oam-remote-failure    Enable timer to recover from OAM detected remote
                       failure
 pagp-flap             Enable timer to recover from pagp-flap error
 port-mode-failure     Enable timer to recover from port mode change failure
 psecure-violation     Enable timer to recover from psecure violation error
 security-violation    Enable timer to recover from 802.1x violation error
 sfp-config-mismatch   Enable timer to recover from SFP config mismatch error
 storm-control         Enable timer to recover from storm-control error
 udld                  Enable timer to recover from udld error
 unicast-flood         Enable timer to recover from unicast flood error
 vmps                  Enable timer to recover from vmps shutdown error
CAT3550(config)#errdisable recovery cause link-flap
CAT3550(config)#^Z
CAT3550#show errdisable recovery
ErrDisable Reason    Timer Status
-----------------    --------------
arp-inspection       Disabled
bpduguard            Disabled
channel-misconfig    Disabled
dhcp-rate-limit      Disabled
dtp-flap             Disabled
gbic-invalid         Disabled
inline-power         Disabled
l2ptguard            Disabled
link-flap            Enabled
mac-limit            Disabled
link-monitor-fail    Disabled
loopback             Disabled
oam-remote-failur    Disabled
pagp-flap            Disabled
port-mode-failure    Disabled
psecure-violation    Disabled
security-violatio    Disabled
sfp-config-mismat    Disabled
storm-control        Disabled
udld                 Disabled
unicast-flood        Disabled
vmps                 Disabled
Timer interval: 300 seconds
Interfaces that will be enabled at the next timeout:
CAT3550#

New Favorite IOS Command

2009-02-07T18:29:00.000-08:00

I know I mentioned this command in passing a few posts ago, but this command has become so valuable to me, it needs its own post. It's the show run | section command. This allows you to define any "major heading" from the IOS configuration and it will filter the running configuration down to just those sections. This is very similar to how the ASA "show run" command works.

For example, I'm working on a book focused around CallManager Express (CME) right now. In CME, you create "ephones" which represent the IP Phones on your network. If I wanted to see the configuration for all my ephones, I can just type:

CME_Voice#show run | s ephone
max-ephones 24
ephone-dn 1
number 1000
ephone-dn 2 dual-line
number 1001
ephone-dn 3 dual-line
number 1003
ephone-dn 10 dual-line
number 1010
huntstop channel
ephone-dn 11
number 1010
preference 1
ephone 1
device-security-mode none
mac-address 0014.1C48.E71A
button 1:10
ephone 2
device-security-mode none
mac-address 0019.D122.DCF3
button 1:11
ephone 3
device-security-mode none
mac-address 0014.A89E.F845
button 1:1 2:2 3:3
ephone 4
device-security-mode none

(FYI - "s" is short for "section") As you can see, this shows all the sections of running-config that start with "ephone", which is all my ephones and ephone-dns (their directory numbers). Gotta love it!

More Handy IOS Filtering Commands

2009-02-07T18:27:00.001-08:00

A list of commands you can use to filter output on a Cisco router:

show run | include <word>
show run | interface <interface>
show run | begin <word>
show run | section include <word>

The "section" command is my newest discovery. For example, if I want to see the configuration of ALL FastEthernet interfaces on my lab router, I could type:

PE1-T1#sh run | section include FastEthernet
interface FastEthernet1/0
description connection to PE1 Internet Router
ip address 51.88.99.2 255.255.255.252
speed 100
full-duplex
interface FastEthernet1/1
no ip address
shutdown
duplex auto
speed auto
interface FastEthernet2/0
no ip address
shutdown
duplex auto
speed auto
interface FastEthernet2/1
ip address 10.7.255.100 255.255.0.0
ip nat outside
ip virtual-reassembly
duplex auto
speed auto
interface FastEthernet3/0
no ip address
shutdown
duplex auto
speed auto
interface FastEthernet3/1
no ip address
shutdown
duplex auto
speed auto

Static NAT Inaccessible Through VPN Connections

2009-02-07T18:25:00.000-08:00

Alright, I've run into this problem three times now and each time I keep having to rediscover the solution, so I thought I'd write the solution here for myself and whomever it may help. Here's the problem:

Creating site-to-site VPN connections as a WAN link replacement is becoming quite common. The problem I continually encounter is the servers behind the router that have Static NAT entries allowing them to be accessible from the outside world become inaccessible through the VPN (using a private address). VPN users can still access the servers by using the Internet connection. This problem occurs simply because of the order in which the Cisco router handles NAT rules.

Take this example. A user from SiteA accesses ServerB at SiteB using its private address on TCP port 80 (HTTP):

UserA ---> Site-to-Site VPN ---> ServerB

The request reaches ServerB who attempts to transmit back to UserA. The router at SiteB has a Static NAT mapping allowing ServerB to be accessible from the Internet. This Static NAT mapping is processed before the site-to-site VPN rule:

ServerB Response ----> Static NAT mapping ---> Reply sent to Internet abyss

The result is the HTTP connection from SiteA times out. So, here's how to fix it:

RouterB(config)#route-map NO_NAT
RouterB(config-route-map)#match ip address 100
RouterB(config-route-map)#exit
RouterB(config)#access-list 100 deny ip host 192.168.15.100 192.168.10.0 0.0.0.255
RouterB(config)#access-list 100 permit ip 192.168.15.0 0.0.0.255 any
RouterB(config)#ip nat inside source static tcp 192.168.15.100 80 81.14.214.29 80 route-map NO_NAT

The above configuration essentially denies the server from going through the Static NAT entry when speaking to hosts across the VPN, but permits it to pass through Static NAT for everything else.

Here's the original Cisco reference:

http://www.cisco.com/warp/public/707/static.html#topic2

Throttle Bandwidth Based on the Time of Day

2009-02-07T18:21:00.000-08:00

Okay...thanks to good-ol Vonage, I've thought of a simple, yet brilliant (in my humble opinion) method to throttle bandwidth based on the time of day. Here's the story: I use Vonage VoIP lines for ALL of my phone lines at home - primarily because I'm cheap, not because of the VoIP "cool factor." The problem? I run a massive file server at home that holds every digital picture, work project, video recording, etc... that I've ever done. Sure, I have a local backup that runs, but I always think "what if the house burns down?!?" so...I have an automated program that backs EVERYTHING up to a remote FTP server anytime things change (add/deletes/etc.) on my file server. The problem? I save so much stuff to the server, the FTP file backup is always running and destroying my Vonage call quality for my home phone. Here's how I fixed it:

Step 1: Create an access-list that matches my file server (172.30.100.11), but only during the day.

Router(config)# time-range DAY (creates a new time range)
Router(config-time-range)# periodic weekdays 6:00 to 22:00 (matches weekdays from 6:00am to 10:00pm)
Router(config-time-range)# periodic weekend 6:00 to 22:00 (matches weekends from 6:00am to 10:00pm)
Router(config-time-range)# exit
Router(config)# ip access-list extended SERVER
Router(config-ext-nacl)# permit ip host 172.30.100.11 any time-range DAY (matches my server during the time-range I specified above)
Router(config-ext-nacl)# exit
Router(config)#

Step 2: Create a class-map (used for QoS) that matches the SERVER access-list we just created.

Router(config)# class-map MATCH_SERVER (MATCH_SERVER is just the name)
Router(config-class-map)# match access-group name SERVER (ties in the access-list above)
Router(config-class-map)# exit
Router(config)#

Step 3: Create a policy-map (used for QoS) that throttles the bandwidth.

Router(config)# policy-map LIMIT_SERVER (creates the policy)
Router(config-pmap)# class MATCH_SERVER (applies policy to this class)
Router(config-pmap-c)# police 80000 (limits bandwidth to 80Kbps)
Router(config-pmap-c)# exit
Router(config-pmap)# exit
Router(config)#

Step 4: Apply the new policy to the incoming interface (the one connected to my LAN, not the Internet).

Router(config)# interface fa0/0
Router(config-if)# service-policy input LIMIT_SERVER

Awesome. Vonage issue solved. Now, I know this is a little cheezy home scenario, but if you think of it, you could apply this logic for any business, any type of traffic, any time of day. You could stretch this to just about any situation!!

from JC

Pasting a Configuration Into Cisco Devices...

2009-02-07T18:18:00.000-08:00

If you've been working with Cisco devices for awhile, you know that the fastest way to backup your configuration is:

1. Do a "show run" command
2. Copy all the output to your clipboard
3. Paste it into notepad

Then, if you need to restore the configuration you just move into global configuration mode and paste all the output back in. Voila! Insta-configured Cisco device. Here's the problem...when you paste in larger configuration files, it fails. Somewhere after about 50-80 lines of config, the input begins to get scrambled and jumbled all around. The reason is the Cisco device cannot keep up with the data that you are entering. So...how do fix this? Slow down the input! Here's how:

All terminal programs have a setting called “Transmit delay msec/line” for the serial port. Here’s a view of what it looks like in Tera Term:

By default, this is some absurdly low value somewhere between 0-10 msec, which means your terminal program will just keep flooding the data and not give the receiving device enough pause to apply it. Adjust this value to something between 35-50 msec and your Cisco device will have no problem keeping up with the data.

from JC

Configuring a Cisco Router to Accept VPN Connections

2009-02-07T18:10:00.000-08:00

This blog has been a long-time-coming as someone asked me quite some time ago to post the simplest way to accomplish this (for a home environment). I hate to admit this, but my home PC (where I get all my email) was hacked since I allowed Microsoft's Remote Desktop Protocol (RDP) and VNC from anywhere on the Internet (very bad idea). That was the end of that - now VPN connections are required to get to my home PC. Well, the simplest way to configure a VPN on a router is to use the Cisco SDM...but Real Cisco Techs™ use the command line :). So here we go:

First thing you need to do is specify an authentication method. Since I'm assuming this is for a home environment, using the local router database is just fine:

Router(config)# aaa authentication login LOCAL_DB local (defines a login method called LOCAL_DB that uses the local DB)
Router(config)# username Jeremy password cisco (creates a user account in the local DB)

Second, you need to define a DHCP pool of addresses for your VPN clients. This is the address range that they will be assigned when they connect. This should be a unique range not in use on your LAN:

Router(config)# ip local pool CLIENT_ADDRESSES 172.30.50.10 172.30.50.20

Next, you have to create an ISAKMP policy. This is a policy that secures Phase 1 of the VPN negotiation. Phase 1 is there to allow you to securely exchange the encryption keys you'll be using for the VPN. Without this phase, someone could sniff your encryption keys and compromise the VPN security:

Router(config)# crypto isakmp policy 1
Router(config-isakmp)# encr aes (my preferred encryption: 128-bit AES; fast and secure)
Router(config-isakmp)# authentication pre-share (says that I'll need to type a secret key on the router & VPN client)
Router(config-isakmp)# group 2 (Diffie-helman group 2...super strong keys to lock down Phase 1)

Now, I need to configure a client configuration group. This is what gives the clients their settings (such as DNS server, IP address, etc...).

Router(config)# crypto isakmp client configuration group HOME
Router(config-isakmp-group)# key s3cr3t (the client has to provide this key to connect to the VPN)
Router(config-isakmp-group)# dns 172.30.100.11 (assigns a DNS server to the client)
Router(config-isakmp-group)# domain ciscoblog.com (assigns a DNS suffix to the client)
Router(config-isakmp-group)# pool CLIENT_ADDRESSES (says that this client will get an IP address from the CLIENT_ADDRESS pool)

There is MUCH more you can put under the above config to define things like split tunneling and access control...but that discussion is for another day :)

Next up, we can configure the settings for the IPSEC tunnel (all this stuff until now has been Phase 1, pre-tunnel info). Initially, we must set up a transform set. This defines what level of encryption (scrambling data so people can't read it) and hashing (checking to make sure data doesn't change) we'd like to use:

Router(config)# crypto ipsec transform-set JEREMYS_SET esp-aes esp-sha-hmac

As a fly-by description, the line above sets the VPN encryption to AES 128-bit and uses SHA-1 (160-bit, I believe) hashing. This is what I'd recommend, but you can choose whatever levels you'd like (just hit the ? key to see all your options).

Now we can create a crypto map. A crypto map takes all these settings and sums them together into something we can apply to an interface:

Router(config)# crypto dynamic-map CLIENT_MAP 1 (creates a dynamic map, which is used for remote access clients)
Router(config-crypto-map)# set transform-set JEREMYS_SET (says that this will be the transform set used for clients)
Router(config-crypto-map)# reverse-route (puts the client IP address in the routing table when the client connects)
Router(config)# crypto map JEREMY_VPN client authentication list LOCAL_DB (links authentication method to the VPN)
Router(config)# crypto map JEREMY_VPN isakmp authorization list LOCAL_DB (links authorization settings - what a user can do - to the VPN)
Router(config)# crypto map JEREMY_VPN client configuration address respond (allows router to respond to DHCP requests from clients)
Router(config)# crypto map JEREMY_VPN 100 ipsec-isakmp dynamic CLIENT_MAP (applies the dynamic crypto map to the real crypto map)

FINALLY, we can apply the crypto map to the interface:

Router(config)# interface fa0/1 (my DSL connection interface)
Router(config-if)# crypto map JEREMY_VPN (applies the crypto map from above)

The router is now ready to accept VPN connections. Now that I'm looking back over this, I'm sure it's generated many more questions than it answered...ask away :)

from JC

3.1 Updated CCNA 2: Routers and Routing Basics

2009-02-07T04:09:00.000-08:00

3.1 Updated CCNA 2: Routers and Routing Basics per Modules(Latest)
Module 1
Module 2
Module 3
Module 4
Module 5
Module 6
Module 7
Module 8
Module 9
Module 10
Module 11
Voucher
Final A
Final B

Updated 3.1 CCNA 1: Networking Basics

2009-01-31T03:41:00.000-08:00

3.1 Updated CCNA 1: Networking Basics per Modules(Latest)
Module 1
Module 2
Module 3
Module 4
Module 5
Module 6
Module 7
Module 8
Module 9
Module 10
Module 11
Final A
Final B

Updated 4.0 CCNA 4: Accessing the WAN

2009-01-28T03:37:00.000-08:00

4.0 Updated CCNA 4: Accessing the WAN per Modules(Latest)
Module 1
Module 2
Module 3
Module 4
Module 5
Module 6
Module 7
Module 8
Final 1
Final 2
Final 3
Final 4

Updated 4.0 CCNA 3: LAN Switching and Wireless

2009-01-25T03:27:00.001-08:00

4.0 Updated CCNA 3: LAN Switching and Wireless per Modules(Latest)
Module 1
Module 2
Module 3
Module 4
Module 5
Module 6
Module 7
Final 1
Final 2

Updated 4.0 CCNA 2: Routing Protocols and Concepts

2009-01-23T18:10:00.000-08:00

4.0 CCNA 2:Routing Protocols and Concept per Modules(Latest)
Module 1
Module 2
Module 3
Module 4
Module 5
Module 6
Module 7
Module 8
Module 9
Module 10
Module 11
Final 1
Final 2

Updated 4.0 CCNA 1:Network Fundamentals

2009-01-21T14:58:00.000-08:00

4.0 CCNA 1:Network Fundamentals per Modules(Latest)
Module 1
Module 2
Module 3
Module 4
Module 5
Module 6
Module 7
Module 8
Module 9
Module 10
Module 11
FINAL 640-802
FINAL SET A
FINAL SET B
FINAL SET C

Other - E-Books - Cisco CCNA Sem 1- 4 Complete Test Answers and Ebook (Updated 2008)

2009-01-02T18:39:00.000-08:00

Files:

CCNA Ebooks\Semester1.rar - 8735056 bytes
CCNA Ebooks\Semester2.rar - 4729118 bytes
CCNA Ebooks\Semester3.rar - 5853847 bytes
CCNA Ebooks\Semester4.rar - 3335703 bytes
CCNA Test Answers\Sem1 Answers\CISCO CCNA Certifications_ CCNA 1_Final.pdf - 147340 bytes
CCNA Test Answers\Sem1 Answers\CISCO CCNA Certifications_ CCNA 1_Module 1.pdf - 133690 bytes
CCNA Test Answers\Sem1 Answers\CISCO CCNA Certifications_ CCNA 1_Module 10.pdf - 134475 bytes
CCNA Test Answers\Sem1 Answers\CISCO CCNA Certifications_ CCNA 1_Module 11.pdf - 132570 bytes
CCNA Test Answers\Sem1 Answers\CISCO CCNA Certifications_ CCNA 1_Module 2.pdf - 133107 bytes
CCNA Test Answers\Sem1 Answers\CISCO CCNA Certifications_ CCNA 1_Module 3.pdf - 135829 bytes
CCNA Test Answers\Sem1 Answers\CISCO CCNA Certifications_ CCNA 1_Module 4.pdf - 132710 bytes
CCNA Test Answers\Sem1 Answers\CISCO CCNA Certifications_ CCNA 1_Module 5.pdf - 134802 bytes
CCNA Test Answers\Sem1 Answers\CISCO CCNA Certifications_ CCNA 1_Module 6.pdf - 133491 bytes
CCNA Test Answers\Sem1 Answers\CISCO CCNA Certifications_ CCNA 1_Module 7.pdf - 133765 bytes
CCNA Test Answers\Sem1 Answers\CISCO CCNA Certifications_ CCNA 1_Module 8.pdf - 131670 bytes
CCNA Test Answers\Sem1 Answers\CISCO CCNA Certifications_ CCNA 1_Module 9.pdf - 134859 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Final Set 2.pdf - 157052 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Final Set 3.pdf - 153401 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Module 1.pdf - 133302 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Module 10.pdf - 130032 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Module 11.pdf - 133230 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Module 2.pdf - 133142 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Module 3.pdf - 132140 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Module 4.pdf - 131485 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Module 5.pdf - 131589 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Module 6.pdf - 131634 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Module 7.pdf - 132413 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Module 8.pdf - 130708 bytes
CCNA Test Answers\Sem2 Answers\CISCO CCNA Certifications_ CCNA 2_Module 9.pdf - 131002 bytes
CCNA Test Answers\Sem3 Answers\CISCO CCNA Certifications_ CCNA 3_Module 1.pdf - 134375 bytes
CCNA Test Answers\Sem3 Answers\CISCO CCNA Certifications_ CCNA 3_Module 2.pdf - 138989 bytes
CCNA Test Answers\Sem3 Answers\CISCO CCNA Certifications_ CCNA 3_Module 3.pdf - 139606 bytes
CCNA Test Answers\Sem3 Answers\CISCO CCNA Certifications_ CCNA 3_Module 4.pdf - 137621 bytes
CCNA Test Answers\Sem3 Answers\CISCO CCNA Certifications_ CCNA 3_Module 5.pdf - 135451 bytes
CCNA Test Answers\Sem3 Answers\CISCO CCNA Certifications_ CCNA 3_Module 6.pdf - 140769 bytes
CCNA Test Answers\Sem3 Answers\CISCO CCNA Certifications_ CCNA 3_Module 7.pdf - 134295 bytes
CCNA Test Answers\Sem4 Answers\module 1.pdf - 105240 bytes
CCNA Test Answers\Sem4 Answers\module 4.pdf - 207389 bytes
CCNA Test Answers\Sem4 Answers\module 5-1.pdf - 255392 bytes
CCNA Test Answers\Sem4 Answers\module 5-2.pdf - 255485 bytes
CCNA Test Answers\Sem4 Answers\module 5-3.pdf - 261815 bytes
CCNA Test Answers\Sem4 Answers\module 6.pdf - 125179 bytes
CCNA Test Answers\Sem4 Answers\module 7.pdf - 394093 bytes
CCNA Test Answers\Sem4 Answers\module 8.pdf - 284867 bytes
CCNA Test Answers\Sem4 Answers\module2.pdf - 244385 bytes
CCNA Test Answers\Sem4 Answers\module3.pdf - 265528 bytes

link download

CCNA ONLINE LAB LINKS

2008-12-19T03:17:00.001-08:00

ACCESS ONLINE

3.1 CCNA 1
3.1 CCNA 2
3.1 CCNA 3
3.1 CCNA 4



 CCNA1/                  16-Jul-2009 16:35    - 

 English/                16-Jul-2009 16:35    -

 CCNA1V3_1_MODULE_1.PDF  04-Jun-2006 23:12  532K
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 CCNA2/                  16-Jul-2009 16:35    -

 CCNA2 v3.1 Module 1.pdf  21-Mar-2007 22:52  582K
 CCNA2 v3.1 Module 10.pdf 21-Mar-2007 22:52  336K
 CCNA2 v3.1 Module 11.pdf 21-Mar-2007 22:52  1.1M
 CCNA2 v3.1 Module 2.pdf  21-Mar-2007 22:52  525K
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 CCNA2 v3.1 Module 4.pdf  21-Mar-2007 22:52  522K
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 CCNA3 v3.1 Module 1.ppt  17-Oct-2006 20:42  1.8M
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CCNA ACL Simulation Q & A

2008-12-18T19:00:00.000-08:00

CCNA ACTUAL EXAM HAVE TWO SIMULATORS.
THE ACL ROUTER SIMULATOR WHICH IS ON ACTUAL CCNA EXAM.

ACL SIM

Answer:

Select the console on Corp1 router

Configuring ACL

Corp1>enable
Corp1#configure terminal
comment: To permit only Host C (192.168.33.3){source addr} to access finance server address (172.22.242.23) {destination addr} on port number 80 (web)
Corp1(config)#access-list 100 permit tcp host 192.168.33.3 host 172.22.242.23 eq 80
comment: To deny any source to access finance server address (172.22.242.23) {destination addr} on port number 80 (web)
Corp1(config)#access-list 100 deny tcp any host 172.22.242.23 eq 80
comment: To permit ip protocol from any source to access any destination because of the implicit deny any any statement at the end of ACL.
Corp1(config)#access-list 100 permit ip any any
Applying the ACL on the Interface
comment: Check show ip interface brief command to identify the interface type and number by checking the IP address configured.
Corp1(config)#interface fa 0/1
If the ip address configured already is incorrect as well as the subnet mask. this should be corrected in order ACL to work
type this commands at interface mode :
no ip address 192.x.x.x 255.x.x.x (removes incorrect configured ip address and subnet mask)
Configure Correct IP Address and subnet mask :
ip address 172.22.242.30 255.255.255.240 ( range of address specified going to server is given as 172.22.242.17 - 172.22.242.30 )

comment: Place the ACL to check for packets going outside the interface towards the finance web server.
Corp1(config-if)#ip access-group 100 out

Corp1(config-if)#end

Important: To save your running config to startup before exit.
Corp1#copy running-config startup-config

Verifying the Configuration :

Step1: show ip interface brief command identifies the interface on which to apply access list .

Step2: Click on each host A,B,C & D . Host opens a web browser page , Select address box of the web browser and type the ip address of finance web server(172.22.242.23) to test whether it permits /deny access to the finance web Server .

Step 3: Only Host C (192.168.33.3) has access to the server . If the other host can also access then maybe something went wrong in your configuration . check whether you configured correctly and in order.

Step 4: If only Host C (192.168.33.3) can access the Finance Web Server you can click on NEXT button to successfully submit the ACL SIM.

from t2k

CCNA - Operations Q# 2

2008-12-18T18:51:00.000-08:00

Question 1:

On a network of one department, there are four PCs connected to a switch, as shown in the following figure:

After the Switch1 restarts. Host A ( the host on the left ) sends the first frame to Host C (the host on the right). What the first thing should the switch do?

A. Switch1 will add 192.168.23.12 to the switching table.
B. Switch1 will add 192.168.23.4 to the switching table.
C. Switch1 will add 000A.8A47.E612 to the switching table.
D. None of the above

Answer: C

Question 2:

The user of Host1 wants to ping the DSL modem/router at 192.168.1.254. Based on the Host1 ARP table that is shown in the exhibit, what will Host1 do?

A. send a unicast ARP packet to the DSL modem/router
B. send unicast ICMP packets to the DSL modem/router
C. send Layer 3 broadcast packets to which the DSL modem/router responds
D. send a Layer 2 broadcast that is received by Host2, the switch, and the DSL modem/router

Answer: B

Question 3:

Which two values are used by Spanning Tree Protocol to elect a root bridge? (Choose two)

A. amount of RAM
B. bridge priority
C. IOS version
D. IP address
E. MAC address
F. speed of the links

Answer: B E

Question 4:

Host 1 is trying to communicate with Host 2. The e0 interface on Router C is down. Which of the following are true? (Choose two.)

A. Router C will use ICMP to inform Host 1 that Host 2 cannot be reached.
B. Router C will use ICMP to inform Router B that Host 2 cannot be reached.
C. Router C will use ICMP to inform Host 1, Router A, and Router B that Host 2 cannot be reached.
D. Router C will send a Destination Unreachable message type.
E. Router C will send a Router Selection message type.
F. Router C will send a Source Quench message type.

Answer: A D

Question 5:

Refer to the exhibit. The network shown in the exhibit is running the RIPv2 routing protocol. The network has converged, and the routers in this network are functioning properly. The FastEthernet0/0 interface on R1 goes down. In which two ways will the routers in this network respond to this change? (Choose two)

A. All routers will reference their topology database to determine if any backup routes to the 192.168.1.0 network are known.
B. Routers R2 and R3 mark the route as inaccessible and will not accept any further routing updates from R1 until their hold-down timers expire.
C. Because of the split-horizon rule, router R2 will be prevented from sending erroneous information to R1 about connectivity to the 192.168.1.0 network.
D. When router R2 learns from R1 that the link to the 192.168.1.0 network has been lost, R2 will respond by sending a route back to R1 with an infinite metric to the 192.168.1.0 network.
E. R1 will send LSAs to R2 and R3 informing them of this change, and then all routers will send periodic updates at an increased rate until the network again converges.

Answer: C D

Question 6:

Which of the following describe the process identifier that is used to run OSPF on a router? (Choose two.)
A. It is locally significant.
B. It is globally significant.
C. It is needed to identify a unique instance of an OSPF database.
D. It is an optional parameter required only if multiple OSPF processes are running on the router.
E. All routers in the same OSPF area must have the same process ID if they are to exchange routing information.

Answer: A C

Question 7:

Refer to the exhibit. The FMJ manufacturing company is concerned about unauthorized access to the Payroll Server. The Accounting1, CEO, Mgr1, and Mgr2 workstations should be the only computers with access to the Payroll Server. What two technologies should be implemented to help prevent unauthorized access to the server? (Choose two)

A. access lists
B. encrypted router passwords
C. STP
D. VLANs
E. VTP
F. wireless LANs

Answer: A D

Question 8:

Which two statements are true about the command ip route 172.16.3.0 255.255.255.0 192.168.2.4? (Choose two.)

A. It establishes a static route to the 172.16.3.0 network.
B. It establishes a static route to the 192.168.2.0 network.
C. It configures the router to send any traffic for an unknown destination to the 172.16.3.0 network.
D. It configures the router to send any traffic for an unknown destination out the interface with the address 192.168.2.4.
E. It uses the default administrative distance.
F. It is a route that would be used last if other routes to the same destination exist.

Answer: A E

Question 9:

Which three statements are correct about RIP version 2? (Choose three.)
A. It has the same maximum hop count as version 1.
B. It uses broadcasts for its routing updates.
C. It is a classless routing protocol.
D. It has a lower default administrative distance than RIP version 1.
E. It supports authentication.
F. It does not send the subnet mask in updates.

Answer: A C E

Question 10:

How should a router that is being used in a Frame Relay network be configured to avoid split horizon issues from preventing routing updates?
A. Configure a separate sub-interface for each PVC with a unique DLCI and subnet assigned to the sub-interface.
B. Configure each Frame Relay circuit as a point-to-point line to support multicast and broadcast traffic.
C. Configure many sub-interfaces on the same subnet.
D. Configure a single sub-interface to establish multiple PVC connections to multiple remote router interfaces.

Answer: A

Question 11:

A network administrator is configuring the routers in the graphic for OSPF. The OSPF process has been started and the networks have been configured for Area 0 as shown in the diagram. The network administrator has several options for configuring RouterB to ensure that it will be preferred as the designated router (DR) for the 172.16.1.0 /24 LAN segment. What configuration tasks could be used to establish this preference? (Choose three)

A. Configure the priority value of the Fa0/0 interface of RouterB to a higher value than any other interface on the Ethernet network.
B. Change the router id of Router B by assigning the IP address 172.16.1.130/24 to the Fa0/0 interface of RouterB.
C. Configure a loopback interface on RouterB with an IP address higher than any IP address on the other routers.
D. Change the priority value of the Fa0/0 interface of RouterB to zero.
E. Change the priority values of the Fa0/0 interfaces of RouterA and RouterC to zero.
F. No further configuration is necessary.

Answer: A C E

from new century

CCNA - Operations Q# 1

2008-12-18T18:49:00.000-08:00

Question 1:

What are two reasons that a network administrator would use access lists? (Choose two.)

A. to control vty access into a router
B. to control broadcast traffic through a router
C. to filter traffic as it passes through a router
D. to filter traffic that originates from the router
E. to replace passwords as a line of defense against security incursions

Answers: A C

Question 2:

A single 802.11g access point has been configured and installed in the center of a square office. A few wireless users are experiencing slow performance and drops while most users are operating at peak efficiency. What are three likely causes of this problem? (Choose three.)

A. mismatched TKIP encryption
B. null SSID
C. cordless phones
D. mismatched SSID
E. metal file cabinets
F. antenna type or direction

Answers: C E F

Question 3:

Refer to the exhibit. How many broadcast domains exist in the exhibited topology?

A. one
B. two
C. three
D. four
E. five
F. six

Answer: C

Question 4:

Which type of attack is characterized by a flood of packets that are requesting a TCP connection to a server?
A. denial of service
B. brute force
C. reconnaissance
D. Trojan horse

Answer: A

Question 5:

Refer to the exhibit.

The network administrator has created a new VLAN on Switch1 and added host C and host D. The administrator has properly configured switch interfaces FastEthernet0/13 through FastEthernet0/24 to be members of the new VLAN. However, after the network administrator completed the configuration, host A could communicate with host B, but host A could not communicate with host C or host D. Which commands are required to resolve this problem?

A. Router(config)# interface fastethernet 0/1.3
Router(config-if)# encapsulation dot1q 3
Router(config-if)# ip address 192.168.3.1 255.255.255.0

B. Router(config)# router rip
Router(config-router)# network 192.168.1.0
Router(config-router)# network 192.168.2.0
Router(config-router)# network 192.168.3.0

C. Switch1# vlan database
Switch1(vlan)# vtp v2-mode
Switch1(vlan)# vtp domain cisco
Switch1(vlan)# vtp server

D. Switch1(config)# interface fastethernet 0/1
Switch1(config-if)# switchport mode trunk
Switch1(config-if)# switchport trunk encapsulation isl

Answer: A

Question 6:

Refer to the exhibit. What is the most efficient summarization that R1 can use to advertise its networks to R2?

A. 172.1.0.0/22

B. 172.1.0.0/21

C. 172.1.4.0/22

D. 172.1.4.0/24
172.1.5.0/24
172.1.6.0/24
172.1.7.0/24

E. 172.1.4.0/25
172.1.4.128/25
172.1.5.0/24
172.1.6.0/24
172.1.7.0/24

Answer: C

Question 7:

Which spread spectrum technology does the 802.11b standard define for operation?

A. IR
B. DSSS
C. FHSS
D. DSSS and FHSS
E. IR, FHSS, and DSSS

Answer: B

Question 8:

A network interface port has collision detection and carrier sensing enabled on a shared twisted pair network. From this statement, what is known about the network interface port?

A. This is a 10 Mb/s switch port.
B. This is a 100 Mb/s switch port.
C. This is an Ethernet port operating at half duplex.
D. This is an Ethernet port operating at full duplex.
E. This is a port on a network interface card in a PC.

Answer: C

Question 9:

Refer to the topology and router configuration shown in the graphic. A host on the LAN is accessing an FTP server across the Internet. Which of the following addresses could appear as a source address for the packets forwarded by the router to the destination server?

A. 10.10.0.1
B. 10.10.0.2
C. 199.99.9.33
D. 199.99.9.57
E. 200.2.2.17
F. 200.2.2.18

Answer: D

Question 10:

Which routing protocol by default uses bandwidth and delay as metrics?
A. RIP
B. BGP
C. OSPF
D. EIGRP

Answer: D

Question 11:

Refer to the exhibit. The networks connected to router R2 have been summarized as a 192.168.176.0/21 route and sent to R1. Which two packet destination addresses will R1 forward to R2? (Choose two)

A. 192.168.194.160
B. 192.168.183.41
C. 192.168.159.2
D. 192.168.183.255
E. 192.168.179.4
F. 192.168.184.45

Answer: B E

Explanation:

From the subnet mask of /21, we can specify the network address and broadcast address of this subnetwork:

Increment: 8 of the third octet(/21 = 255.255.248.0 or 1111 1111.1111 1111. 1111 1000.0000 0000)
Network address: 192.168.176.0
Broadcast address: 192.168.183.255 (183 = 176 + 8 - 1)

Therefore all the destination addresses in this range will be forwarded to R2 -> B and E lie in this range and their packages will be forwarded to R2. Please notice that D is an incorrect answer because it is a broadcast address and R1 will drop its packages.

Question 12:

Refer to the exhibit. Which switch provides the spanning-tree designated port role for the network segment that services the printers?

A. Switch1
B. Switch2
C. Switch3
D. Switch4

Answer: C

Explanation:

First, the question asks what switch services the printers, so it can be Switch 3 or Switch 4 which is connected directly to the Printers.

Next, by comparing the MAC address of Switch 3 and Switch 4 we found that the MAC of Switch 3 is smaller. Therefore the interface connected to the Printers of Switch 3 will become designated interface and the interface of Switch 4 will be blocked

(Please notice that Switch 1 will become the root bridge because of its lowest priority, not Switch 3)

from new century

CCNA - Access List Questions

2008-12-18T18:47:00.000-08:00

Question 1:

Refer to the exhibit. The access list has been configured on the S0/0 interface of router RTB in the outbound direction. Which two packets, if routed to the interface, will be denied? (Choose two)

access-list 101 deny tcp 192.168.15.32 0.0.0.15 any eq telnet
access-list 101 permit ip any any

A. source ip address: 192.168.15.5; destination port: 21
B. source ip address:, 192.168.15.37 destination port: 21
C. source ip address:, 192.168.15.41 destination port: 21
D. source ip address:, 192.168.15.36 destination port: 23
E. source ip address: 192.168.15.46; destination port: 23
F. source ip address:, 192.168.15.49 destination port: 23

Answer: D E

Question 2:

Refer to the graphic. It has been decided that PC1 should be denied access to Server. Which of the following commands are required to prevent only PC1 from accessing Server1 while allowing all other traffic to flow normally? (Choose two)

A - Router(config)# interface fa0/0
Router(config-if)# ip access-group 101 out
B - Router(config)# interface fa0/0
Router(config-if)# ip access-group 101 in
C - Router(config)# access-list 101 deny ip host 172.16.161.150 host 172.16.162.163
Router(config)# access-list 101 permit ip any any
D - Router(config)# access-list 101 deny ip 172.16.161.150 0.0.0.255 172.16.162.163 0.0.0.0
Router(config)# access-list 101 permit ip any any

Answer: B C

Question 3:

Refer to the exhibit. Why would the network administrator configure RA in this manner?

A. to give students access to the Internet
B. to prevent students from accessing the command prompt of RA
C. to prevent administrators from accessing the console of RA
D. to give administrators access to the Internet
E. to prevent students from accessing the Internet
F. to prevent students from accessing the Admin network

Answer: B

Question 4:

An access list was written with the four statements shown in the graphic. Which single access list statement will combine all four of these statements into a single statement that will have exactly the same effect?

A. access-list 10 permit 172.29.16.0 0.0.0.255
B. access-list 10 permit 172.29.16.0 0.0.1.255
C. access-list 10 permit 172.29.16.0 0.0.3.255
D. access-list 10 permit 172.29.16.0 0.0.15.255
E. access-list 10 permit 172.29.0.0 0.0.255.255

Answer: C

from new century

CCNA Implementation SIM

2008-12-18T18:44:00.000-08:00

This topology contains 3 routers and 1 switch. Complete the topology.

Drag the appropriate device icons to the labeled Device
Drag the appropriate connections to the locations labeled Connections.
Drag the appropriate IP addresses to the locations labeled IP address

(Hint: use the given host addresses and Main router information)
To remove a device or connection, drag it away from the topology.

Use information gathered from the Main router to complete the configuration of any additional routers. No passwords are required to access the Main router. The config terminal command has been disabled for the HQ router. The router does not require any configuration.

Configure each additional router with the following:

Configure the interfaces with the correct IP address and enable the interfaces.
Set the password to allow console access to consolepw
Set the password to allow telnet access to telnetpw
Set the password to allow privilege mode access to privpw

Note: Because routes are not being added to the configurations, you will not be able to ping through the internetwork.
All devices have cable autosensing capabilities disabled.
All hosts are PC’s

Answer and explanation:

Specify appropriate devices and drag them on the "Device" boxes

For the device at the bottom-right box, we notice that it has 2 interfaces Fa0/2 and Fa0/4 -> it is a switch

The question stated that this topology contains 3 routers and 1 switch -> two other devices are routers

Place them on appropriate locations as following:

(Host D and host E will be automatically added after placing two routers. Click on them to access neighboring routers)

Specify appropriate connections between these devices:

+ The router on the left is connected with the Main router through FastEthernet interfaces: use a crossover cable
+ The router on the right is connected with the Main router through Serial interfaces: use a serial cable
+ The router on the right and the Switch: use a straight-through cable
+ The router on the left and the computer: use a crossover cable

Assign appropriate IP addresses for interfaces:

From Main router, use show running-config command:

(Notice that you may see different IP addresses in the real CCNA exam, the ones shown above are just used for demonstration)

From the output we learned that the ip address of Fa0/0 interface of the Main router is 192.168.152.178/28. This address belongs to a subnetwork which has:

Increment: 16 (/28 = 255.255.255.240 or 1111 1111.1111 1111.1111 1111.1111 0000)
Network address: 192.168.152.176 (because 176 = 16 * 11 and 176 < class="blueandbold">Broadcast address: 192.168.152.191 (because 191 = 176 + 16 - 1)

And we can pick up an ip address from the list that belongs to this subnetwork: 192.168.152.190 and assign it to the Fa0/0 interface the router on the left

Use the same method for interface Serial0/0 with an ip address of 192.168.152.172

Increment: 16
Network address: 192.168.152.160 (because 160 = 16 * 10 and 160 < class="blueandbold">Broadcast address: 192.168.152.175 (because 176 = 160 + 16 - 1)

-> and we choose 192.168.152.174 for Serial0/0 interface of the router on the right

Interface Fa0/1 of the router on the left

IP (of the computer on the left) : 192.168.152.129/28

Increment: 16
Network address: 192.168.152.128 (because 128 = 16 * 8 and 128 < class="blueandbold">Broadcast address: 192.168.152.143 (because 143 = 128 + 16 - 1)

-> we choose 192.168.152.142 from the list

Interface Fa0/0 of the router on the right

IP (of the computer on the left) : 192.168.152.225/28

Increment: 16
Network address: 192.168.152.224 (because 224 = 16 * 14 and 224 < class="blueandbold">Broadcast address: 192.168.152.239 (because 239 = 224 + 16 - 1)

-> we choose 192.168.152.238 from the list

Let's have a look at the picture below to summarize

Configure two routers on the left and right with these commands:

Router1 = router on the left

Assign appropriate IP addresses to Fa0/0 & Fa0/1 interfaces:

Router1>enable
Router1#configure terminal
Router1(config)#interface fa0/0
Router1(config-if)#ip address 192.168.152.190 255.255.255.240
Router1(config-if)#no shutdown

Router1(config)#interface fa0/1
Router1(config-if)#ip address 192.168.152.142 255.255.255.240
Router1(config-if)#no shutdown

Set passwords (configure on two routers)

+ Console password:

Router1(config-if)#exit
Router1(config)#line console 0
Router1(config-line)#password consolepw
Router1(config-line)#login
Router1(config-line)#exit

+ Telnet password:

Router1(config)#line vty 0 4
Router1(config-line)#password telnetpw
Router1(config-line)#login
Router1(config-line)#exit

+ Privilege mode password:

Router1(config)#enable password privpw

Save the configuration:

Router1(config)#exit
Router1#copy running-config startup-config

Configure IP addresses of Router2 (router on the right)

Router2>enable
Router2#configure terminal
Router2(config)#interface fa0/0
Router2(config-if)#ip address 192.168.152.238 255.255.255.240
Router2(config-if)#no shutdown

Router2(config-if)#interface serial0/0
Router2(config-if)#ip address 192.168.152.174 255.255.255.240
Router2(config-if)#no shutdown

and set console, telnet and privilege mode passwords for Router2 as we did for Router1, remember to save the configuration when you finished

from new century

CCNA Drag and Drop Questions

2008-12-18T18:43:00.000-08:00

Question 1:

A dental firm is redesigning the network that connects its three locations. The administrator gave the networking team 192.168.164.0 to use for addressing the entire netwok. After subnetting the address, the team is ready to assign the addresses. The administrator plans to configure ip subnet-zero and use RIP v2 as the routing protocol. As a member of the networking team, you must address the network and at the same time conserver unused addresses for future growth. With those goals in mind, drag the host addresses on the left to the correct router interface. Once of the routers is partially configured. Move your mouse over a router to view its configuration. Not all of the host addresses on the left are necessary.

Answer:

Question 2:

In order to complete a basic switch configuration, drag each switch IOS command on the left to its purpose on the right

Answer:

1) enable
2) configure terminal
3) hostname
4) Interface vlan 1
5) no shutdown
6) ip address
7) ip default-gateway

Question 3:

The Missouri branch office router is connected through its s0 interface to the Alabama Headquarters router s1 interface. The Alabama router has two LANs. Missouri users obtain Internet access through the Headquarters router. The network interfaces in the topology are addressed as follows: Missouri: e0 - 192.168.35.17/28; s0 - 192.168.35.33/28; Alabama: e0 - 192.168.35.49/28; e1 - 192.168.35.65/28; s1 - 192.168.35.34/28. The accounting server has the address of 192.168.35.66/28. Match the access list conditions on the left with the goals on the right. (Not all options on the left are used.)

Answer:

1) deny ip 192.168.35.16 0.0.0.15 host 192.16.35.66

2) deny ip 192.168.35.55 0.0.0.0 host 192.168.35.66

3) permit ip 192.168.35.0 0.0.0.255 host 192.168.35.66

Question 4:

A host with the address of 192.168.125.34/27 needs to be denied access to all hosts outside its own subnet. To accomplish this, complete the command in brackets, [access-list 100 deny protocol address mask any], by dragging the appropriate options on the left to their correct placeholders on the right.

Answer:

1) ip

2) 192.168.125.34

3) 0.0.0.0

Full command: access-list 100 deny ip 192.168.125.34 0.0.0.0

Question 5:

Drag and drop the network user application to the appropriate description of its primary use (not all options are used)

Answer:

1) web browser

2) instant message

3) e-mail

4) database

5) collaboration

Question 6:

This topology contains 3 routers and 1 switch. Complete the topology.

Drag the appropriate device icons to the labeled Device
Drag the appropriate connections to the locations labeled Connections.
Drag the appropriate IP addresses to the locations labeled IP address

(Hint: use the given host addresses and Main router information)
To remove a device or connection, drag it away from the topology.

Use information gathered from the Main router to complete the configuration of any additional routers. No passwords are required to access the Main router . The config terminal command has been disabled for the HQ router. The router does not require any configuration.

Configure each additional router with the following

Note: Because routes are not being added to the configurations, you will not be able to ping through the internetwork.
All devices have cable autosensing capabilities disabled.
All hosts are PC’s

Answer:

CCNA - Hotspot Questions

2008-12-18T18:41:00.000-08:00

Hotspot Routing Question

Question 1:

If the router R1 has a packet with a destination address 192.168.1.255, what describes the operation of the network?

A - R1 will forward the packet out all interfaces
B - R1 will drop this packet because it is not a valid IP address
C - As R1 forwards the frame containing this packet, Sw-A will add 192.168.1.255 to its MAC table
D - R1 will encapsulate the packet in a frame with a destination MAC address of FF-FF-FF-FF-FF-FF
E - As R1 forwards the frame containing this packet, Sw-A will forward it ti the device assigned the IP address of 192.168.1.255

Answer: B

Question 2:

Users on the 192.168.1.0/24 network must access files located on the Server 1. What route could be configured on router R1 for file requests to reach the server?

A - ip route 0.0.0.0 0.0.0.0 s0/0/0
B - ip route 0.0.0.0 0.0.0.0 209.165.200.226
C - ip route 209.165.200.0 255.255.255.0 192.168.1.250
D - ip route 192.168.1.0 255.255.255.0 209.165.100.250

Answer: A

Quetion 3:

When a packet is sent from Host 1 to Server 1, in how many different frames will the packet be encapsulated as it is sent across the internetwork?

A - 0
B - 1
C - 2
D - 3
E - 4

Answer: D

Question 4:

What must be configured on the network in order for users on the Internet to view web pages located on Web Server 2?

A - On router R2,configure a default static route to the 192.168.1.0 network
B - On router r2, configure DNS to resolve the URL assigned to Web Server 2 to the 192.168.1.10 address
C - On router R1, configure NAT to translate an address on the 209.165.100.0/24 network to 192.168.1.10
D - On router R1, configure DHCP to assign a registered IP address on the 209.165.100.0/24 network to Web Server 2

Answer: C

Question 5:

The router address 192.168.1.250 is the default gateway for both the Web Server 2 and Host 1. What is the correct subnet mask for this network?

A - 255.255.255.0
B - 255.255.255.192
C - 255.255.255.250
D - 255.255.255.252

Answer: A

Hotspot Frame-relay Question

Question 1:

What destination Layer 2 address will be used in the frame header containing a packet for host 172.30.4.4?

A - 704
B - 196
C - 702
D - 344

Answer: C

Question 2:

A static map to the S-AMER location is required. Which command should be used to create this map?

A - frame-relay map ip 172.30.0.3 704 broadcast
B - frame-relay map ip 172.30.0.3 196 broadcast
C - frame-relay map ip 172.30.0.3 702 broadcast
D - frame-relay map ip 172.30.0.3 344 broadcast

Answer: B

Question 3:

Which connection uses the default encapsulation for serial interfaces on Cisco routers?

A - The serial connection to the MidEast branch office
B - The serial connection to the DeepSouth branch office
C - The serial connection to the NorthCentral branch office
D - The serial connection to the Multinational Core

Answer: A

Question 4:

If required, what password should be configured on the router in the MidEast branch office to allow a connection to be established with the Dubai router?

A - No password is required
B - Enable
C - Scr
D - Telnet
E - Console

Answer: D

from new century

CCNA Troubleshooting Q# 2

2008-12-18T18:40:00.001-08:00

Question 1:

A network administrator is troubleshooting the OSPF configuration of routers R1 and R2. The routers cannot establish an adjacency relationship on their common Ethernet link. The graphic shows the output of the show ip ospf interface e0 command for routers R1 and R2. Based on the information in the graphic, what is the cause of this problem?

A. The OSPF area is not configured properly.
B. The priority on R1 should be set higher.
C. The cost on R1 should be set higher.
D. The hello and dead timers are not configured properly.
E. A backup designated router needs to be added to the network.
F. The OSPF process ID numbers must match.

Answer: D

Question 2:

This graphic shows the results of an attempt to open a Telnet connection to router ACCESS1 from router Remote27. Which of the following command sequences will correct this problem?

A. ACCESS1(config)# line console 0
ACCESS1(config-line)# password cisco
B. Remote27(config)# line console 0
Remote27(config-line)# login
Remote27(config-line)# password cisco
C. ACCESS1(config)# line vty 0 4
ACCESS1(config-line)# login
ACCESS1(config-line)# password cisco
D. Remote27(config)# line vty 0 4
Remote27(config-line)# login
Remote27(config-line)# password cisco
E. ACCESS1(config)# enable password cisco
F. Remote27(config)# enable password cisco

Answer: C

Question 3:

Refer to the exhibit. A network administrator attempts to ping Host2 from Host1 and receives the results that are shown. What is a possible problem?

A. The link between Host1 and Switch1 is down.
B. TCP/IP is not functioning on Host1
C. The link between Router1 and Router2 is down.
D. The default gateway on Host1 is incorrect.
E. Interface Fa0/0 on Router1 is shutdown.
F. The link between Switch1 and Router1 is down.

Answer: C

Question 4:

Refer to the exhibit. Hosts in network 192.168.2.0 are unable to reach hosts in network 192.168.3.0. Based on the output from RouterA, what are two possible reasons for the failure? (Choose two)

A. The cable that is connected to S0/0 on RouterA is faulty.
B. Interface S0/0 on RouterB is administratively down.
C. Interface S0/0 on RouterA is configured with an incorrect subnet mask.
D. The IP address that is configured on S0/0 of RouterB is not in the correct subnet.
E. Interface S0/0 on RouterA is not receiving a clock signal from the CSU/DSU.
F. The encapsulation that is configured on S0/0 of RouterB does not match the encapsulation that is configured on S0/0 of RouterA.

Answer: E F

Question 5:

When upgrading the IOS image, the network administrator receives the exhibited error message. What could be the cause of this error?

A. The new IOS image is too large for the router flash memory.
B. The TFTP server is unreachable from the router.
C. The new IOS image is not correct for this router platform.
D. The IOS image on the TFTP server is corrupt.
E. There is not enough disk space on the TFTP server for the IOS image.

Answer: B

from new century

CCNA Troubleshooting Q# 1

2008-12-18T18:38:00.000-08:00

Question 1:

Refer to the exhibit. The network administrator is in a campus building distant from Building B. WANRouter is hosting a newly installed WAN link on interface S0/0. The new link is not functioning and the administrator needs to determine if the correct cable has been attached to the S0/0 interface. How can the administrator accurately verify the correct cable type on S0/0 in the most efficient manner?

A. Telnet to WANRouter and execute the command show interfaces S0/0
B. Telnet to WANRouter and execute the command show processes S0/0
C. Telnet to WANRouter and execute the command show running-configuration
D. Telnet to WANRouter and execute the command show controller S0/0
E. Physically examine the cable between WANRouter S0/0 and the DCE.
F. Establish a console session on WANRouter and execute the command show interfaces S0/0

Answer: D

Question 2:

Two routers named Atlanta and Brevard are connected by their serial interfaces as shown in the exhibit, but there is no data connectivity between them. The Atlanta router is known to have a correct configuration. Given the partial configurations shown in the exhibit, what is the problem on the Brevard router that is causing the lack of connectivity?

A. A loopback is not set
B. The IP address is incorrect.
C. The subnet mask is incorrect.
D. The serial line encapsulations are incompatible.
E. The maximum transmission unit (MTU) size is too large.
F. The bandwidth setting is incompatible with the connected interface.

Answer: B

Question 3:

Refer to the exhibit. The two exhibited devices are the only Cisco devices on the network. The serial network between the two devices has a mask of 255.255.255.252. Given the output that is shown, what three statements are true of these devices? (Choose three)

A. The Manchester serial address is 10.1.1.1.
B. The Manchester serial address is 10.1.1.2.
C. The London router is a Cisco 2610.
D. The Manchester router is a Cisco 2610.
E. The CDP information was received on port Serial0/0 of the Manchester router.
F. The CDP information was sent by port Serial0/0 of the London router.

Answer: A C E

Question 4:

A network administrator has configured two switches, named London and Madrid, to use VTP. However, the switches are not sharing VTP messages. Given the command output shown in the graphic, why are these switches not sharing VTP messages?

A. The VTP version is not correctly configured.
B. The VTP operating mode is not correctly configured.
C. The VTP domain name is not correctly configured.
D. VTP pruning mode is disabled.
E. VTP V2 mode is disabled.
F. VTP traps generation is disabled.

Answer: C

Question 5:

The network shown in the diagram is experiencing connectivity problems. Which of the following will correct the problems? (Choose two.)

A. Configure the gateway on Host A as 10.1.1.1.
B. Configure the gateway on Host B as 10.1.2.254.
C. Configure the IP address of Host A as 10.1.2.2.
D. Configure the IP address of Host B as 10.1.2.2.
E. Configure the masks on both hosts to be 255.255.255.224.
F. Configure the masks on both hosts to be 255.255.255.240.

Answer: B D

Question 6:

Refer to the exhibit:

A. Router(config)# interface fastethernet 0/1.3
Router(config-if)# encapsulation dot1q 3
Router(config-if)# ip address 192.168.3.1 255.255.255.0

B. Router(config)# router rip
Router(config-router)# network 192.168.1.0
Router(config-router)# network 192.168.2.0
Router(config-router)# network 192.168.3.0

C. Switch1# vlan database
Switch1(vlan)# vtp v2-mode
Switch1(vlan)# vtp domain cisco
Switch1(vlan)# vtp server

D. Switch1(config)# interface fastethernet 0/1
Switch1(config-if)# switchport mode trunk
Switch1(config-if)# switchport trunk encapsulation isl

Answers: A

Question 7:

Refer to the exhibit. Hosts on the same VLAN can communicate with each other but are unable to communicate with hosts on different VLANs. What is needed to allow communication between VLANs?

A. a switch with a trunk link that is configured between the switches
B. a router with an IP address on the physical interface that is connected to the switch
C. a switch with an access link that is configured between the switches
D. a router with subinterfaces configured on the physical interface that is connected to the switch

Answer: D

Question 8:

The show interfaces serial 0/0 command resulted in the output shown in the graphic. What are possible causes for this interface status? (Choose three)

A. The interface is shut down.
B. No keepalive messages are received.
C. The clockrate is not set.
D. No loopback address is set.
E. No cable is attached to the interface.
F. There is a mismatch in the encapsulation type.

Answer: B C F

Question 9:

While troubleshooting a connectivity issue from a PC you obtain the following information:
Local PC IP address: 10.0.0.35/24
Default Gateway: 10.0.0.1

Remote Sever: 10.5.75.250/24

You then conduct the following tests from the local PC:
Ping 127.0.0.1 - Successful
Ping 10.0.0.35 - Successful
Ping 10.0.0.1 - Unsuccessful
Ping 10.5.75.250 - Unsuccessful

What is the underlying cause of this problem?

A - A remote physical layer problem exists.
B - The host NIC is not functioning.
C - TCP/IP has not been correctly installed on the host.
D - A local physical layer problem exists.

Answer: D

from new century

CCNA WAN Questions

2008-12-18T18:37:00.000-08:00

Question 1:

The command frame-relay map ip 10.121.16.8 102 broadcast was entered on the router. Which of the following statements is true concerning this command?

A: This command should be executed from the global configuration mode.

B: The IP address 10.121.16.8 is the local router port used to forward data.

C: 102 is the remote DLCI that will receive the information.

D: This command is required for all Frame Relay configurations.

E: The broadcast option allows packets, such as RIP updates, to be forwarded across the PVC.

Correct Answers: E

Explanation:

The command frame-relay map ip 10.121.16.8 102 broadcast means to mapping the distal IP 10.121.16.8 102 to the local DLCI 102. When the "broadcast" keyword is included, it turns Frame Relay network as a broadcast network, which can forward broadcasts

Question 2:

Refer to the exhibit. Which statement describes DLCI 17?

A: DLCI 17 describes the ISDN circuit between R2 and R3.

B: DLCI 17 describes a PVC on R2. It cannot be used on R3 or R1.

C: DLCI 17 is the Layer 2 address used by R2 to describe a PVC to R3.

D: DLCI 17 describes the dial-up circuit from R2 and R3 to the service provider.

Correct Answers: C

Explanation:

DLCI stands for Data Link Connection Identifier. DLCI values are used on Frame Relay interfaces to distinguish between different virtual circuits. DLCIs have local significance because the identifier references the point between the local router and the local Frame Relay switch to which the DLCI is connected.

Question 3:

A default Frame Relay WAN is classified as what type of physical network?

A: point-to-point

B: broadcast multi-access

C: nonbroadcast multi-access

D: nonbroadcast multipoint

E: broadcast point-to-multipoint

Correct Answer: C

Explanation:

Non-Broadcast Multi-Access (NBMA) networks are types such as Frame Relay, X.25, and Asynchronous Transfer Mode (ATM). These networks allow for multi-access, but have no broadcast ability like Ethernet

Question 4:

Which of the following are key characteristics of PPP? (Choose three.)

A: can be used over analog circuits

B: maps Layer 2 to Layer 3 address

C: encapsulates several routed protocols

D: supports IP only

E: provides error correction

Correct Answers: A C E

Explanation:

No more explanation needed, below is some more information about PPP:

PPP (Point-to-Point Protocol) allows authentication such as Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP) and multilink connections (allow several separate physical paths to appear to be one logical path at layer 3) and can be run over asynchronous and synchronous links.

Question 5:

Which three Layer 2 encapsulation types would be used on a WAN rather than a LAN? (Choose three)

A: HDLC

B: Ethernet

C: Token Ring

D: PPP

E: FDDI

F: Frame Relay

Correct Answer: A D F

Question 6:

Refer to the exhibit. What is the meaning of the term dynamic as displayed in the output of the show frame-relay map command shown?

A: The Serial0/0 interface is passing traffic.

B: The DLCI 100 was dynamically allocated by the router

C: The Serial0/0 interface acquired the IP address of 172.16.3.1 from a DHCP server

D: The DLCI 100 will be dynamically changed as required to adapt to changes in the Frame Relay cloud

E: The mapping between DLCI 100 and the end station IP address 172.16.3.1 was learned through Inverse ARP

Correct Answer: E

Explanation:

The term dynamic indicates that the DLCI number and the remote router IP address 172.16.3.1 are learned via the Inverse ARP process.

Inverse ARP is a technique by which dynamic mappings are constructed in a network, allowing a device such as a router to locate the logical network address and associate it with a permanent virtual circuit (PVC).

Question 7:

Which of the following describes the roles of devices in a WAN? (Choose three.)

A: A CSU/DSU terminates a digital local loop

B: A modem terminates a digital local loop

C: A CSU/DSU terminates an analog local loop

D: A modem terminates an analog local loop

E: A router is commonly considered a DTE device

F: A router is commonly considered a DCE device

Correct Answers: A D E

Explanation:

The idea behind a WAN is to be able to connect two DTE networks together through a DCE network. The network’s DCE device (includes CSU/DSU) provides clocking to the DTE-connected interface (the router’s serial interface).

Question 8:

How should a router that is being used in a Frame Relay network be configured to avoid split horizon issues from preventing routing updates?

A: Configure a separate sub-interface for each PVC with a unique DLCI and subnet assigned to the sub-interface

B: Configure each Frame Relay circuit as a point-to-point line to support multicast and broadcast traffic

C: Configure many sub-interfaces on the same subnet

D: Configure a single sub-interface to establish multiple PVC connections to multiple remote router interfaces

Correct Answer: A

Explanation:

Look at the figure below:

In the figure, router R1 has two point-to-point subinterfaces. The s0.1 subinterface connects to router R3 and the s0.2 subinterface connects to router R2. Each subinterface is on a different subnet.

Question 9:

What can a network administrator utilize by using PPP Layer 2 encapsulation? (Choose three.)

A: VLAN support

B: compression

C: authentication

D: sliding windows

E: multilink support

F: quality of service

Correct Answers: B C E

Explanation:

Same as question 4

Question 10:

The Frame Relay network in the diagram is not functioning properly. What is the cause of the problem?

A: The Gallant router has the wrong LMI type configured

B: Inverse ARP is providing the wrong PVC information to the Gallant router

C: The S3 interface of the Steele router has been configured with the frame-relay encapsulation ietf command

D: The frame-relay map statement in the Attalla router for the PVC to Steele is not correct

E: The IP address on the serial interface of the Attalla router is configured incorrectly

Correct Answer: D

Explanation:

At Attalla router, we find a deleted status but the next map statement indicates an active status, which if for Gallant. Therefore we can deduce the map statement for the PVC from Attalla to Steele is incorrect. Incorrect DLCI assignments that are configured normally shown up as "deleted" in the frame relay maps.

from new century

CCNA Configuration SIM Question

2008-12-18T18:35:00.000-08:00

Question:
To configure the router (R2-RC) click on the console host icon that is connected to a router by a serial console cable (shown in the diagram as a dashed black line)

Central Florida Widgets recently installed a new router in their office. Complete the network installation by performing the initial router configurations and configuring RIPV2 routing using the router command line interface (CLI) on the R2-RC.
Name of the router is R2-RC
Enable-secret password is cisco1
The password to access user EXEC mode using the console is cisco2
The password to allow telnet access to the router is cisco3
IPV4 addresses must be configured as follows:
Ethernet network 209.165.202.128/27 - router has last assignable host address in subnet
Serial network is 192.0.2.16/28 - router has last assignable host address in the subnet. Interfaces should be enabled.
Router protocol is RIP V2
Attention :
In practical examinations, please note the following, the actual information will prevail.
1. Name of the router is xxx
2. Enable-secret password is xxx
3. Password to access user EXEC mode using the console is xxx
4. The password to allow telnet access to the router is xxx
5. IP information

Solution:
1) Name the router:
Router>enable
Router#configurate terminal
Router(config)#hostname R2-RC

2) Set secret password:
R2-RC(config)# enable secret cisco1

3) Set password for the console:
R2-RC(config)#line console 0
R2-RC(config-line)#password cisco2
R2-RC(config-line)#login
R2-RC(config-line)#exit

4) Set the Telnet password:
R2-RC(config)#line vty 0 4
R2-RC(config-line)#password cisco3
R2-RC(config-line)#login
R2-RC(config-line)#exit

5) Assign IP address for Ethernet interface (Fa0/0):
The Ethernet network 209.165.202.128/27 has:
Increment:32 (/27 = 255.255.255.224 or 1111 1111.1111 1111.1111 1111.1110 0000)
Network address: 209.165.202.128
Broadcast address: 209.165.202.159 (because 128 + 32 - 1 = 159)
Therefore the last assignable host address in this subnet is 209.165.202.158 and we will assign it to Fa0/0 interface with these commands:
R2-RC(config)# interface fa0/0
R2-RC(config-if)#ip address 209.165.202.158 255.255.255.224
R2-RC(config-if)#no shutdown
R2-RC(config-if)#exit

6) Assign IP address for Serial interface (S0/0/0):
Serial network 192.0.2.16/28 has:
Increment:16 (/28 = 255.255.255.240 or 1111 1111.1111 1111.1111 1111.1111 0000)
Network address: 192.0.2.16
Broadcast address: 192.0.2.31 (because 16 + 16 - 1 = 31)
So the last assignable host address in this subnet is 192.0.2.30. Finally we assign it to s0/0/0 interface:
R2-RC(config)# interface s0/0/0
R2-RC(config-if)#ip address 192.0.2.30 255.255.255.240
R2-RC(config-if)#no shutdown
R2-RC(config-if)#exit

7) Configure RIP v2 routing protocol:
R2-RC(config)#router rip
R2-RC(config-router)#version 2
R2-RC(config-router)#network 209.165.202.128
R2-RC(config-router)#network 192.0.2.16
R2-RC(config-router)#end
R2-RC#copy running-config startup-config

from new century

DOWNLOAD CISCO E-BOOK

2008-12-17T03:15:00.000-08:00

The following links are external links only and no file is being uploaded on blogger’s server. If any of these links violates copyright, please inform us, we will remove that link(s) immediately.

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from svetulcho.org

CCNA 4 DISCOVERY CURRICULUM

2008-12-16T03:47:00.000-08:00

CCNA 4: Discovery - Introducing Routing and Switching in the Enterprise

Module 1: Introducing Network Design Concepts

Module 2: Gathering Network Requirements

Module 3: Characterizing the Existing Network

Module 4: Identifying Application Impacts on Network Design

Module 5: Creating the Network Design

Module 6: Using IP Addressing in the Network Design

Module 7: Prototyping the Campus Network

Module 8: Prototyping the WAN

Module 9: Preparing the Proposal

Module 10: Course Summary

CCNA Semester 4 Labs and Worksheets

CCNA 3 DISCOVERY CURRICULUM

2008-12-16T03:46:00.000-08:00

CCNA 3: Discovery - Introducing Routing and Switching in the Enterprise

Module 1: Networking in the Enterprise

Module 2: Exploring the Enterprise Network Infrastructure

Module 3: Switching in an Enterprise Network

Module 4: Addressing in an Enterprise Network

Module 5: Routing with a Distance Vector Protocol

Module 6: Routing with a Link-State Protocol

Module 7: Implementing Enterprise WAN Links

Module 8: Filtering Traffic Using Access Control Lists

Module 9: Troubleshooting an Enterprise Network

Module 10: Course Summary

CCNA Semester 3 Labs and Worksheets

CCNA 2 DISCOVERY CURRICULUM

2008-12-16T03:45:00.000-08:00

CCNA 2: Discovery - Working at a Small-to-Medium Business or ISP

Chapter 1: The Internet and its Uses

Chapter 2: Help Desk

Chapter 3: Planning a Network Upgrade

Chapter 4: Planning the Addressing Structure

Chapter 5: Configuring Network Devices

Chapter 6: Routing

Chapter 7: ISP Services

Chapter 8: ISP Responsibility

Chapter 9: Course Summary

CCNA Semester 2 Labs and Worksheets

CCNA 1 DISCOVERY CURRICULUM

2008-12-16T03:39:00.000-08:00

CCNA 1: Discovery - Networking for Home and Small Businesses

Chapter 1: Personal Computer Hardware

Chapter 2: Operating Systems

Chapter 3: Connecting to the Network

Chapter 4: Connecting to the Internet Through an ISP

Chapter 5: Network Addressing

Chapter 6: Network Services

Chapter 7: Wireless Technologies

Chapter 8: Basic Security

Chapter 9: Troubleshooting Your Network

Chapter 10: Course Summary

CCNA Semester 1 Labs and Worksheets

Questions & Answers - CCNA 1 Module 1

2008-12-07T00:44:00.000-08:00

1. Several computers in the company require new NICs. A technician has located a good price on the Internet for the purchase of these NICs. Before these NICs are purchased and installed, what details must be verified? (Choose three.)

A) The MAC address on the NIC

B) The size of the RAM on the NIC

C) The bandwidth supported by the NIC

D) The type of media supported by the NIC

E) The type of network architecture supported by the NIC

Explanation: After reading the material “What is a Network Interface Card,” we find out that a MAC address is unique to every NIC. Therefore, we don’t really have a need to be selective, and thus A is wrong. And NICs do have RAM, but it isn’t as vital to a NIC as it is for something like your computer- so B is wrong. The remaining three answers are therefore correct.

2. What is the hexadecimal equivalent for the binary number 00100101?

A) 15

B) 20

C) 25

D) 30

E) 37

F) 40

Explanation: The above problem involves converting a binary number to a hexadecimal number. The above article explains that to do so, you need to split the binary number into two nibbles and then find their decimal value. After you find the decimal value, you may finally find the hex number. Consult the article above more a more in-depth explanation.

3. Which phrases describe a byte? (Choose two.)

A) a single binary digit

B) +5 volts of electricity

C) the value range 0 to 127

D) a grouping of eight binary digits

E) a single addressable data storage location

Explanation: From reading the above article, we know that one binary digit is a bit, not a byte- A is wrong. +5 volts of electricity may in some instances indicate a bit, but certainly not a byte- B is wrong. C is wrong because the value ranges from 0 to 255, not 127. Finally we get D and E as our answers- since we know that there are 8 bits in a byte, and each byte is considered to be a single addressable data storage location.

4. Which specialized equipment is used to make a physical connection from a PC to a network?

A) router

B) RAM

C) CD ROM

D) network interface card

Explanation: You don’t necessarily need to read the above article to know this answer. RAM and CD-ROM components do not take a part in a network- and a router, like the name implies, routes data rather than connects a PC to a network. Obviously, the answer should be D.

5. What is the binary equivalent for the decimal number 248?

A) 11100000

B) 11110000

C) 11110100

D) 11111000

Explanation: The above question wants you to convert the number 248 to binary. By reading the above article, we know that to do so we need to see which bits fit into 248. This is commonly done by the “Will this number go into 248?” method. If you need more of a descript explanation (complete with diagrams), consult the above article.

6. Convert the binary number 01011011 into its hexadecimal equivalent. Select the correct answer from the list below.

A) 5A

B) 5B

C) 5C

D) 5D

E) 6B

F) 7A

7. What is the binary equivalent for decimal number 149?

A) 10010111

B) 10010101

C) 10011001

D) 10010111

E) 10101011

F) 10101101

Explanation: The above question wants you to convert the number 149 to binary. By reading the above article, we know that to do so we need to see which bits fit into 149. This is commonly done by the “Will this number go into 149?” method. If you need more of a descript explanation (complete with diagrams), consult the above article.

8. In an 8 bit binary number, what is the total number of combinations of the eight bits?

A) 128

B) 254

C) 255

D) 256

E) 512

F) 1024

Explanation: This question can be tricky. By reading the above article, we know that it is either 255 or 256. We know that we can go up to 255 with each byte of data. But don’t be so sure it’s C- it is, in fact, D. This is because we count 0 as a number, and thus, there are 256 combinations. Be on the lookout for more sly questions Cisco throws at us to make sure we’re still awake.

9. Which device connects a computer with a telephone line by providing modulation and demodulation of incoming and outgoing data?

A) NIC

B) CSU/DSU

C) router

D) modem

E) telco switch

Explanation: This question should be fairly easy. If you know the definition of a modem, you should get this question right even without our help. Nonetheless, the article above will provide extra information on modems if needed.

10. What is the binary equivalent for the decimal number 162?

A) 10101010

B) 10100010

C) 10100100

D) 10101101

E) 10110000

F) 10101100

Explanation: The above question wants you to convert the number 162 to binary. By reading the above article, we know that to do so we need to see which bits fit into 162. This is commonly done by the “Will this number go into 162?” method. If you need more of a descript explanation (complete with diagrams), consult the above article.

11. Which of the following are popular web browsers? (Choose two.)

A) Acrobat

B) Internet Explorer

C) Macromedia Flash

D) Netscape Navigator

E) Quicktime

F) World Wide Web

Explanation: This is another question that you should know from basic computer knowledge. Although we ourselves hesitated and asked, “Where’s FireFox, and why is Netscape Navigator on the list?” (It seems Cisco is a little behind on the times.)

12. Convert the Base 10 number 116 into its eight bit binary equivalent. Choose the correct answer from the following list:

A) 01111010

B) 01110010

C) 01110100

D) 01110110

E) 01110111

F) 01010110

Explanation: The above question wants you to convert the number 116 to binary. By reading the above article, we know that to do so we need to see which bits fit into 116. This is commonly done by the “Will this number go into 116?” method. If you need more of a descript explanation (complete with diagrams), consult the above article.

13. What is the hexadecimal equivalent for the binary number 10001110?

A) 22

B) 67

C) 142

D) AE

E) 8E

14. Represented as a decimal number, what is the result of the logical ANDing of binary numbers 00100011 and 11111100?

A) 3

B) 32

C) 35

D) 220

E) 255

Explanation: This question involves the AND logical operator. Essentially, you compare the two binary numbers. If there is a binary 1 in the same location of both numbers, then you count that bit. Think of it as a test: you need 1 AND 1 for any addition to take place. A binary 1 and binary 0, or binary 0 and binary 0, will both not work. B is the correct answer since the 5th bit from the right is the only bit that can be ANDed- and 2^5 = 32. (Note that it is not the 6th bit, since we start counting at 0, not 1.)

15. Convert the decimal number 231 into its binary equivalent. Select the correct answer from the list below.

A) 11110010

B) 11011011

C) 11110110

D) 11100111

E) 11100101

F) 11101110

Explanation: The above question wants you to convert the number 231 to binary. By reading the above article, we know that to do so we need to see which bits fit into 231. This is commonly done by the “Will this number go into 231?” method. If you need more of a descript explanation (complete with diagrams), consult the above article.

16. What are three conditions that would require a network administrator to install a new NIC? (Choose three.)

A) whenever a NIC is damaged

B) when there is a need to provide a secondary or backup NIC

C) when there is a change from copper media to wireless

D) whenever operating system security patches are applied

E) whenever the PC has been moved to a different location

Explanation: A is correct since when something is broke, we should fix it (or in this case replace it). Obviously if we have the need for a backup NIC, we will need to install a new one- B is correct too. C is correct since some NICs are specific to a certain type of media, so changing that media warrants a new NIC. D is not true since the operating system does not have an effect on the NIC. E is not true because the physical location of a computer will not interfere with your NIC.

Questions & Answers - CCNA 1 Module 2

2008-12-07T00:41:00.000-08:00

1. Which layer of the OSI model provides network services to processes in electronic mail and file transfer programs?

A) data link

B) transport

C) network

D) application

Explanation: This question is rather basic, and shouldn’t need much explaining. If you’re still lost or aren’t sure of the right answer, consult the above material for confirmation.

2. Which of the following are data link layer encapsulation details? (Choose two.)

A) A header and trailer are added.

B) Data is converted into packets.

C) Packets are packaged into frames.

D) Frames are divided into segments.

E) Packets are changed into bits for Internet travel.

Explanation: Since each layer encapsulates the information with a header and trailer, A is correct. At the Data Link Layer, we do not convert the information into a packet- so B is wrong. Rather, we convert the packets into frames- so C is correct. D and E also incorrect since they do not follow the encapsulation process correctly- review the above material if you’d like a more thorough explanation.

3. Which three features apply to LAN connections? (Choose three.)

A) operate using serial interfaces

B) make network connection using a hub

C) limited to operation over small geographic areas

D) provide part-time connectivity to remote services

E) typically operate under local administrative control

F) provide lower bandwidth services compared to WANs

Explanation: From reading the above article, we know that WANs use serial interfaces, not LANs, so A is incorrect. Since we can indeed make a network connection using a hub, B is correct. C is also correct- it corresponds with the exact definition of a LAN. D is incorrect, since LANs do not access remote services. E is correct, as it also corresponds with the definition of a LAN. F is incorrect since LANs provide much more bandwidth than WANs.

4. Which layer of the OSI model provides connectivity and path selection between two end systems where routing occurs?

A) physical layer

B) data link layer

C) network layer

D) transport layer

Explanation: Path selection is not available on the physical layer- A is incorrect. The Data Link Layer provides an interface to the NIC, so B is incorrect as well. The Network Layer supports logical addressing and routing- and therefore, C is correct. The Transport Layer would be incorrect since it is responsible for and end-to-end connection, not necessarily path selection.

5. Which term describes the process of adding headers to data as it moves down OSI layers?

A) division

B) encoding

C) separation

D) segmentation

E) encapsulation

Explanation: Division, encoding, separation, and segmentation all do not make sense in this instance. Logically, only encapsulation could be the correct answer. Follow the link above for more information on encapsulation.

6. Refer to the following list. Choose the correct order of data encapsulation when a device sends information.

1. segments

2. bits

3. packets

4. data

5. frames

A) 1 - 3 - 5 - 4 - 2

B) 2 - 1 - 3 - 5 - 4

C) 2 - 4 - 3 - 5 - 1

D) 4 - 3 - 1 - 2 - 5

E) 4 - 1 - 3 - 5 - 2

F) 3 - 5 - 1 - 2 - 4

Explanation: The encapsulation process in the OSI model is quite easy- by reading the above material we can remember the pneumonic “Dirty Sick People Feel Bad,” whereas each letter of each word stands for Data, Segments, Packets, Frames, Bits.

7. The central hub has malfunctioned in the network. As a result, the entire network is down. Which type of physical network topology is implemented?

A) bus

B) star

C) ring

D) mesh

Explanation: By reading the link on network topology, we know that the only choice above that is a centralized topology is the Star Topology. All other topologies are decentralized- which would of course not correspond with the question as it states “central hub.”

8. Which of the following are factors that determine throughput? (Choose two.)

A) types of passwords used on servers

B) type of Layer 3 protocol used

C) network topology

D) width of the network cable

E) number of users on the network

Explanation: The above guide to bandwidth and throughput states that the network topology and number of users on the network both influences throughput- so C and E are both correct. Passwords, layer 3 protocols, and width of cable are either ambiguous or wouldn’t load down throughput.

9. Which best describes the function of the physical layer?

A) Defines the electrical and functional specifications for the link between end systems.

B) Provides reliable transit of data across a physical link.

C) Provides connectivity and path selection between two end systems.

D) Concerned with physical addressing, network topology and media access.

Explanation: The above introduction to the TCP/IP model states that the physical layer is concerned with physical aspects of a network. It doesn’t provide a reliable connection- B is incorrect as other layers do this. The Physical Layer is fairly “dumb,” so it doesn’t do path selection either- C is incorrect. Again, the Physical Layer isn’t smart enough for media access, so D is wrong. A is therefore correct.

10. Which of the following are ways that bandwidth is commonly measured? (Choose three.)

A) GHzps

B) kbps

C) Mbps

D) Nbps

E) MHzps

F) Gbps

Explanation: This question should be fairly easy- although the above link will help you out if you are a little rusty. B, C, and F are all correct by definition.

11. Which of the following are layers of the TCP/IP model? (Choose three.)

A) Application

B) Physical

C) Internet

D) Network Access

E) Presentation

Explanation: This should be another fairly easy question. The TCP/IP model does not have the Presentation or Physical layer- the OSI model does, however. Likewise, A, C, and D are correct.

12. What is the term used to describe the transport layer protocol data unit?

A) bits

B) packets

C) segments

D) frames

E) data streams

Explanation: By reading the above article, we know that the Transport Layer corresponds with segments. (You may also have remembered the pneumonic “Dirty Sick People Feel Bad,” whereas S stands for Segments.)

13. What makes it easier for different networking vendors to design software and hardware that will interoperate?

A) OSI model

B) proprietary designs

C) IP addressing scheme

D) standard logical topologies

E) standard physical topologies

Explanation: The clear choice here is A- the OSI model. Proprietary designs would actually make it harder for networking vendors to provide compatible hardware and software. The rest of the answers do not directly apply to networking vendors and their products.

14. Refer to the exhibit. Which column shows the correct sequence of OSI model layers?

A) A

B) B

C) C

D) D

Explanation: This is another simple question. You can review the above article, or you may have remembered the pneumonic “Please Do Not Throw Sausage Pizza Away,” whereas each letter of each word corresponds to an OSI model layer.

15. What is one advantage of defining network communication by the seven layers of the OSI model?

A) It increases the bandwidth of a network.

B) It makes networking easier to learn and understand.

C) It eliminates many protocol restrictions.

D) It increases the throughput of a network.

E) It reduces the need for testing network connectivity.

Explanation: The only answer above that would even apply to the OSI model would be B- as it is much easier to understand as compared to the TCP/IP model. All other answers assume that the OSI model has an actual influence on network design- it doesn’t. It is simply a learning model.

16. Which two features apply to WAN connections? (Choose two.)

A) operate using serial interfaces

B) make network connection using a hub

C) limited to operation over small geographic areas

D) typically operate under local administrative control

E) provide lower bandwidth services compared to LANs

Explanation: Both A and E are correct, as defined in the above article. B, C, and D apply to LANs, not WANs.

17. A switch has failed in the network. As a result, only one segment of the network is down. Which type of physical network topology is implemented?

A) bus

B) ring

C) star

D) extended star

Explanation: Bus and Ring topologies do not use switches, so A and B is incorrect. C is incorrect because if the switch failed on a Star Topology, the entire network would be down. Thus, D is correct. Review the article above for more information.

18. Refer to the exhibit. Identify the devices labeled A, B, C, and D in the network physical documentation.

A) A=bridge, B=switch, C=router, D=hub

B) A=bridge, B=hub, C=router, D=switch

C) A=bridge, B=router, C=hub, D=switch

D) A=hub, B=bridge, C=router, D=switch

Explanation: B is correct- it shows the diagram of each device correctly. This should be very basic networking knowledge, and thus, no further explanation is needed.

Questions & Answers - CCNA 1 Module 3

2008-12-07T00:39:00.000-08:00

1. What are two advantages of using UTP cable in a networking environment? (Choose two.)

A) is stiffer than STP

B) is less expensive than fiber

C) is easier to install than coaxial

D) provides longer distances than coaxial provides

E) is less susceptible to outside noise sources than fiber is

Explanation: A is incorrect, since we don’t ever recall the stiffness of a cable being a factor in cable advantages. B is true, since fiber is a newer technology, that likewise is more expensive to produce. C is also true, since coaxial can be a pain to install- unlike UTP cable. D and E are both untrue since coaxial provides longer distance, and fiber isn’t susceptible to most outside interference.

2. What are two advantages of using fiber-optic cabling instead of UTP? (Choose two.)

A) lower cost

B) easer to install

C) allows longer distances

D) less effected by external signals

E) easier to terminate the cable ends

Explanation: A is incorrect, since fiber-optic media is still fairly expensive. And although it is fairly easy to install, UTP is much easier- B is also incorrect. C is true since we use modulated light waves to transmit data- which can travel vast distances as compared to copper media. D is also true for the same reason- we aren’t using electric signals in fiber optic media, which means no electro-magnetic interference. E is untrue, since UTP cable doesn’t need to be terminated at all.

3. What is the difference between a wireless NIC and an Ethernet NIC?

A) The Ethernet NIC operates at 100 Mbps, whereas a wireless NIC operates at 10 Mbps.

B) The Ethernet NIC uses a PCI expansion slot, and a wireless NIC cannot use an expansion slot.

C) The wireless NIC uses CSMA/CA, whereas a Ethernet NIC uses token passing as an access method.

D) The wireless NIC associates to an access point, and an Ethernet NIC attaches to a hub or switch using a cable.

E) The Ethernet NIC attaches to a hub or a switch using only fiber cabling, and a wireless NIC attaches to a wireless antenna using air as a network medium.

Explanation: Since the type of NIC doesn’t necessarily dictate operation speed, A is not correct. B is also incorrect, since both use expansion slots. C is incorrect, since the NIC again does not necessarily dictate the network type. D is true, since we know that wireless signals need an access point, and Ethernet NICs connect to hubs/switches. Finally, E is incorrect since we aren’t limited to fiber optic media on Ethernet NICs.

4. Which wireless standard operates in the 5 GHZ transmission range and is capable of 54 Mbps of data throughput?

A) 802.11

B) 802.11a

C) 802.11b

D) 802.11g

Explanation: From reading the above article, we know that only one of the above standards operates at 5 GHZ. Click the above link to learn more.

5. A company is converting a cabled LAN to a wireless Ethernet LAN. What must be changed on every host on the network?

A) No changes are required.

B) Each host will require a new IP address.

C) Each host will require an appropriate NIC or adapter.

D) Each host will require that the operating system be upgraded.

Explanation: A is incorrect since we will indeed need to change the NIC. B is incorrect since we don’t necessarily need to rearrange our IP addresses. C is correct, since we will need to obtain a wireless NIC as opposed to the Ethernet NIC. D is also incorrect since the operating system has no influence on the question at hand.

6. Refer to the exhibit. Which answer correctly identifies the pinout of the UTP cables labeled Cable A, Cable B, and Cable C?

A) A=straight, B=rollover, C=crossover

B) A=rollover, B=crossover, C=straight

C) A=crossover, B=straight, C=straight

D) A=crossover, B=straight, C=rollover

E) A=straight, B=crossover, C=rollover

F) A=rollover, B=straight, C=crossover

Explanation: From reading the above article, we know that the above pinouts only match one of the listed answers. Read the above article for more information.

7. What factors should be considered when selecting the appropriate cable for connecting a PC to a network? (Choose two.)

A) type of system bus

B) motherboard model

C) distance of cable run

D) speed of transmission

E) computer manufacturer

Explanation: A and B are both incorrect since they do not relate to the wiring process of a network. C and D are both factors in the process, so they are correct. E is incorrect, for the same reason A and B were- it does not have a part in the wiring process.

8. Which Ethernet implementation requires the signal on the media to be boosted at a maximum distance of 100 meters?

A) 10BASE2

B) 10BASE5

C) 100BASE-T

D) 100BASE-FX

E) 1000BASE-CX

Explanation: There is a handy diagram in the above article that will explain the distance implementations of the above choices. Click the above link for more information.

9. When is a straight-through cable used in a network?

A) when configuring a router

B) when connecting a host to a host

C) when connecting a switch to a router

D) when connecting one switch to another switch

Explanation: The above article explains which instance a straight-through cable is used- refer to it for further information.

10. What type of cable is used to make an Ethernet connection between a host and a LAN switch?

A) console

B) rollover

C) crossover

D) straight-through

Explanation: The above article explains which cable should be used in this instance- refer to it for further information.

11. Which of the following are used for data communication signals? (Choose three.)

A) light patterns

B) electrical voltages

C) controlled air pulses

D) mixed media impulses

E) magnetized fluid wave

F) modulated electromagnetic waves

Explanation: The above article explains that light patterns, electrical voltages, and modulated electromagnetic waves are all used for communication. Thus, A, B, and F are correct.

12. What does UTP cable rely on to reduce signal degradation caused by EMI and RFI?

A) shielding

B) magnetism

C) cancellation

D) insulation

E) properly grounded connections

F) RJ-45 connectors

Explanation: We know from the above article that EMI and RFI can both be reduced via cancellation- particularly, in the twisting of the wires inside the cable.

13. Select the characteristics specified by 10BaseT. (Choose three.)

A) twisted pair cable

B) T style connectors

C) baseband transmission

D) 10 gigabits per second data rate

E) 10 megabits per second data

F) decimal encoded data transmission

Explanation: The above article explains that we can break down what a cable’s specifications are through its name. The 10 means that it may transmit 10 megabits per second- E is correct. The T means it is a twisted pair cable- A is correct. Base means that it is a baseband transmission- so C is also correct.

14. Refer to the exhibit. What type of cable connects the two routers together without any intermediary device?

A) console

B) rollover

C) crossover

D) straight-through

Explanation: The above article explains which cable we would use to connect two like devices- a router and a router.

15. Which cable connectors are used to connect a cable from a router’s console port to a PC? (Choose two.)

A) RJ-11

B) RJ-12

C) RJ-45

D) DB-8

E) DB-9

F) DB-10

Explanation: Since the above is fairly basic terminology, we should know that RJ-45 and DB-9 are both correct. Thus, C and E are the correct choices.

Questions & Answers - CCNA 1 Module 4

2008-12-07T00:38:00.000-08:00

1. To ensure reliable LAN communications, what should a technician be looking for when attaching connectors to the ends of UTP cable?

A) that the white-orange/orange pair is attached first

B) That the wire pairs remain twisted as much as possible

C) that one end of the shield is properly ground but not the other

D) that 50 ohm termination resistors are on both ends

Explanation: Since we know that crosstalk is commonly caused from not keeping wires twisted correctly, we whould look for that first- B is correct. UTP cable isn’t grounded, so C is incorrect. Resistors are used on UTP cable, so D is also incorrect. A is incorrect since it would be rather pointless, unless the wire pairs appear to be twisted and the problem can not be found.

2. Which of the following describes frequency?

A) length of each wave

B) height of each wave

C) number of cycles each second

D) amount of time between each wave

Explanation: Frequency is defined in the article above as “cycles per second,” so C is correct.

3. How are binary ones and zeros represented in fiber optic installations? (Choose two.)

A) +5 volts/-5 volts

B) 0 volts/5 volts

C) light/no light

D) high to low electrical transition

E) low to high electrical transition

F) increasing/decreasing light intensity

Explanation: Fiber optic cable uses light to initiate communication- therefore, we can say that C and F are both correct. Voltage is associated with electricity, not light- and therefore the rest of the answers are incorrect.

4. What is expected when crosstalk is present in networks with higher transmission frequencies? (Choose two.)

A) jitter

B) increase in crosstalk

C) higher signal attenuation

D) increases in cancellation effect

E) destruction of more of the data signal

Explanation: As a higher frequency is obtained, more destruction of the data signal is present, and crosstalk increases. B and D are correct.

5. A small company is experiencing difficulties on its LAN. After performing some tests, a technician has determined that the copper media supporting the LAN is experiencing abnormal attenuation. What are two possible causes of the problem? (Choose two.)

A) defective connectors

B) excessively long cable lengths

C) use of higher grade cabling

D) low frequency signals used in the media

E) network cable runs isolated from other cables

Explanation: Since many problems will be with connectors or long cable lengths, that is what we should check first. The signal degrades over time, so excessive distances will weaken the signal. Connectors that don’t function properly will also, of course, distort or attenuate our signal.

6. What factors need to be considered to limit the amount of signal attenuation in Ethernet cable runs? (Choose two.)

A) type of users

B) number of users

C) length of cable

D) type of electrical equipment

E) installation of connectors on the cable

Explanation: This question directly corresponds to the one above- and therefore, we know that C and E are both correct.

7. What conditions are described when transmission signals from one wire pair affects another wire pair? (Choose two.)

A) noise

B) resistance mismatch

C) jitter

D) crosstalk

E) attenuation

Explanation: We know from the above article that crosstalk and noise both result from signals jumping from one wire to another. Resistance mismatch, jitter, and attenuation are unrelated.

8. What is a cause of crosstalk in UTP cable?

A) cable pairs that are shorted

B) cable pairs crossed during termination

C) cabling runs installed in separate conduit

D) cable pairs that are untwisted because of poor termination of the cable

Explanation: It should be apparent by now that the number one cause of crosstalk is faulty connectors or untwisted wires- therefore, D is correct.

9. Which of the following are detected by the wire map test? (Choose three.)

A) near-end crosstalk (NEXT)

B) opens

C) propagation delay

D) return loss

E) reversed-pair faults

F) short circuits

Explanation: Opens, reversed-pair faults, and short circuits are all detected by a wire map test. We need to use special features of a testing device to test for NEXT, propagation delay, and return loss. It’s possible to test for these things, but not with a wire map.

10. A company needs to extend the LAN to six separate buildings. To limit the amount of signal attenuation on the LAN media, what type of media would be the best to use between the buildings?

A) air (wireless)

B) coaxial cable

C) fiber

D) shielded twisted pair

E) unshielded twisted pair

Explanation: Since fiber can be run for longer distances, and isn’t effected by outside interference, the company should use fiber; C is correct. Wireless would be a poor choice since walls would interfere with the signal. STP and UTP would both be vulnerable to interference, and would also have a much shorter distance capability.

Questions & Answers - CCNA 1 Module 5

2008-12-06T16:48:00.000-08:00

1. Refer to the exhibit. What is the appropriate cable to use at each of the numbered network connections?

A) 1-crossover; 2-straight-through; 3-crossover; 4-straight-through

B) 1-straight-through; 2-crossover; 3-straight-through; 4-straight-through

C) 1-straight-through; 2-crossover; 3-crossover; 4-straight-through

D) 1-rollover; 2-crossover; 3-straight-through; 4-straight-through

E) 1-rollover; 2-straight-through; 3-straight-through; 4-straight-through

Explanation: In the first computer, we are connecting it to a router’s console port- and so we will need a rollover cable. The second computer is linked to the Ethernet port, so it needs a crossover cable. The router to switch connection requires a straight-through cable, since they are unlike devices. The switch and the workstation are also unlike devices, so it is also a straight-through cable. D is correct.

2. Which two devices are considered OSI Layer 1 devices? (Choose two.)

A) hubs

B) routers

C) bridges

D) switches

E) repeaters

Explanation: OSI Layer 1 devices reside on the Physical Layer. These are considered “dumb” devices- both hubs and repeaters reside on this layer. A and E are correct.

3. What device is used to connect hosts to an Ethernet LAN and requires a straight-through UTP cable between the hosts and this device?

A) NIC

B) router

C) switch

D) server

Explanation: While you could say that the above answers all may be able to connect hosts to a LAN, only the switch would require a straight-through cable, since the host and switch are unlike devices. Note that the NIC is an integral component of a computer- so it doesn’t have any type of Ethernet cable connecting it to a computer. (Only cable connecting it to a network.)

4. What is the most common type of cabling used in LANs?

A) STP

B) UTP

C) coax

D) fiber

Explanation: Single Twisted-Pair is quite popular, since it is cheap, easy to install, and quite durable. Each other method suffers from high cost or are rather difficult to install.

5. In which situations would a crossover cable be used to connect devices in a network? (Choose two.)

A) switch to PC

B) switch to hub

C) switch to router

D) switch to server

E) switch to switch

Explanation: The above article states that we use a crossover cable when connecting like devices- so B and E are both correct.

6. Refer to the exhibit. How many collision domains exist in the network?

A) 1

B) 2

C) 4

D) 7

E) 8

Explanation: Switches only create one collision domain. Since there are two connections to each part of the network, there are two collision domains- B is correct.

7. What type of cable would be used to make the connection between the console port of a router and a workstation?

A) crossover

B) rollover

C) straight-through

D) patch

Explanation: The above article states that to enter the console port, we need to use a rollover cable- B is correct.

8. Which function is a unique responsibility of the DCE devices shown in the exhibit?

A) transmission of data

B) reception of data

C) clocking for the synchronous link

D) noise cancellation in transmitted data

Explanation: The clocking rate must be set on the DCE side of the cable, or communication will not take place. C is correct.

9. Which address does a bridge use to make filtering and switching decisions?

A) source MAC

B) source IP

C) destination MAC

D) destination IP

E) network IP address

Explanation: The bridge uses the destination MAC, since it is a layer two device. The source MAC would be impractical, since we need a “to” address, not a “from” address. C is correct.

10. What is characteristic of how a hub operates?

A) A hub selectively drops packets that represent potential security risks.

B) A hub forwards data out all interfaces except the inbound interface.

C) A hub dynamically learns the interfaces to which all devices are attached.

D) At start up, a hub queries the devices on all interfaces in order to learn the MAC addresses of the attached devices.

E) A hub transmits a frame to a specific interface based on the destination MAC address.

Explanation: The above article states that hubs forward data out all interfaces, except the inbound interface. Thus, B is corect. Unfortunately, hubs are dumb devices and do not work with MAC addresses, so A, C, D, and E are all incorrect

11. Users with systems that are attached to a hub are complaining about poor response time. What device could replace the hub and provide immediate response time improvement?

A) router

B) switch

C) bridge

D) repeater

E) A hub transmits a frame to a specific interface based on the destination MAC address.

Explanation: Since hubs split bandwidth between all interfaces, this can be a very poor performing device. Switches use microsegmentation to give bandwidth only to interfaces that need it at a specific time- so B is correct.

12. Which of the following are benefits of peer-to-peer networks? (Choose three.)

A) centralized security

B) easy to create

C) very scalable

D) no centralized equipment required

E) centralized administrator not required

F) centralized control of assets

Explanation: Peer to peer networks are easy to create and are considered to be decentralized. This means that B, D, and E are all correct. The client/server model is centralized, and harder to create- which would apply to A, C, and F.

13. Which statement is accurate about a WAN link?

A) The link transmits data serially.

B) The link uses a maximum distance of 100 meters.

C) The link uses the same transmission rate as all other WAN links use.

D) The link uses the same standardized connector style that is used for all WAN technologies.

Explanation: We know from the above article that WANs use serial connections to communicate. The transmission rate can be changed, so C is wrong. Different connectors may be used, so D is wrong. B is also wrong, since the maximum distance may be much longer than that- after all, the internet is a rather large WAN that spans the entire Earth.

14. Which items in the exhibit are DTE devices?

A) A and B

B) B and C

C) C and D

D) A and D

E) A, B, C, and D

Explanation: D is the correct answer, since routers A and D both act as the client in the given scenario. To put it into perspective, you can imagine that each router is your home network, and your computer is connected to the router. Thus, you are the client.

15. At which layer of the OSI model does the MAC address of a NIC reside?

A) physical

B) application

C) network

D) transport

E) data link

F) session

Explanation: The MAC address is a Layer 2 function- the Data Link Layer. E is the correct answer.

16. Refer to the exhibit. A technician measured the lengths of the CAT 5e structured cable runs in the exhibit. How should the technician evaluate the cabling shown in the diagram to the network administrator?

A) All cabling to work areas are within specifications.

B) Station A and B may experience intermittent problems because the length exceeds the recommended standard.

C) Station B may experience intermittent problems because the length exceeds the recommended standard.

D) Station C may experience intermittent network connectivity because the length is less than the recommended standard.

E) Station A and B will have intermittent problems because the length exceeds the recommended standard.

F) Station C will not have network connectivity because the length is less than the recommended standard.

Explanation: If you check the distance specifications in the above article, you’ll notice that computer B is over the limit. Thus, C is the correct answer.

17. Which statement describes a typical use of Gigabit Ethernet?

A) to provide high-speed desktop connectivity for average users

B) to provide connectivity to low to medium volume applications

C) to provide medium volume connectivity to workgroup servers

D) to provide high-speed connectivity for backbones and cross connects

Explanation: Gigabit Ethernet is commonly used for backbone cabling, since that is where the most traffic is present. D is correct. Refer to the above article for more information.

18. The ends of a UTP cable are shown in the exhibit. Which cable configuration is shown?

A) crossover

B) rollover

C) reversed-pair

D) straight-through

E) split-pair

F) console

Explanation: The above configuration matches the specification of a straight-through cable, D is correct.

19. The ends of a UTP cable are shown in the exhibit. Which cable configuration is shown?

A) console

B) crossover

C) rollover

D) reversed-pair

E) split-pair

F) straight-through

Explanation: The above configuration matches the specification of a crossover cable, B is correct.

20. Which of the following are benefits of a wireless network? (Choose two.)

A) higher data speeds

B) better security

C) mobility

D) less expensive NIC cards

E) no need to run cables to hosts

Explanation: This question should be fairly obvious. Without wires, you have more mobility- C is correct. For the same reason, E is also correct. The other results may be true in some cases, but it really depends on how the network is configured to judge its security or speed.

Questions & Answers - CCNA 1 Module 6

2008-12-06T16:45:00.000-08:00

Refer to the exhibit. Host A is communicating with host F. What happens to a frame sent from host A to host F as it travels over the Ethernet segments?

A) The frame format is modified as it passes through each switch.
B) The frame format remains the same across each Ethernet segment.
C) The frame format is modified as the media speed changed at switch B and switch
D) The frame format is modified as the media material changes between copper and fiber at switch C and switch D.

Explanation: The frame format is not modified at any point to its destination, so B is the correct answer.

2. How many hexadecimal digits are in a MAC address?

A) 2
B) 8
C) 12
D) 16
E) 32

Explanation: Hexadecimal is outlined in the above article, and we will find from reading it that there are 12 digits in a hexadecimal MAC address. C is the correct answer.

3. What are three functions of a NIC in a PC? (Choose three.)

A) A NIC connects the PC to the network media.
B) A NIC detects collisions on the Ethernet segment.
C) A NIC checks the formatting of data before it is transmitted.
D) A NIC passes the contents of selected frames to the upper OSI layers.
E) A NIC acknowledges and retransmits data that was not received properly.
F) A NIC discards frames when the destination IP address does not match the local host.

Explanation: The NIC connects a PC to network media, so A is correct. It also detects collisions, so B is also correct. A NIC is too dumb of a device to check formatting, so C is incorrect. NICs do indeed pass information to upper OSI layers, so D is correct. D and E are both untrue since NICs do not have these responsibilities.

4. At what layer of the OSI model does a MAC address reside?

A) 1
B) 2
C) 3
D) 4
E) 7

Explanation: The second layer of the OSI model is the Data link layer (which corresponds to the TCP/IP network access layer). We know that the data link layer is responsible for MAC address capability, so B is the correct answer.

5. A router has an Ethernet, Token Ring, serial, and ISDN interface. Which interfaces will have a MAC address?

A) serial and ISDN interfaces
B) Ethernet and Token Ring interfaces
C) Ethernet and ISDN interfaces
D) Token Ring and serial interfaces

Explanation: The MAC address is reserved for the Ethernet and Token Ring interfaces, so B is correct. Serial and ISDN interfaces do not require MAC addresses, so the remaining answers are incorrect.

6. In an Ethernet LAN, how does the NIC know when it can transmit data?

A) An Ethernet NIC transmits data as soon as the frame is received.
B) An Ethernet NIC transmits data as soon as the NIC receives a token.
C) An Ethernet NIC transmits data when it senses a collision.
D) An Ethernet NIC transmits data after listening for the absence of a signal on the media.

Explanation: NICs look for an absence in signal before transmitting, since we need an open spot on the network to transmit or there will be collisions. D is the correct answer.

7. Which characteristics describe carrier sense multiple access collision detect (CSMA/CD)? (Choose three.)

A) reliable
B) point-to-point
C) nondeterministic
D) connection-oriented
E) collision environment
F) first-come, first-served approach

Explanation: CSMA/CD is a first come first serve approach, as stated in the above article- F is correct.. This is basically defining nondeterministic, so C is correct too. CSMA/CD works with the collision environment, so E is also true.

8. Which two devices can provide full-duplex Ethernet connections? (Choose two.)

A) hub
B) modem
C) repeater
D) NIC
E) Layer 2 switch

Explanation: This question is rather tricky. It is best to eliminate the wrong answers first. Hubs can’t, since they don’t support microsegmentation. Modems operate as half-duplex, so they are out too. Repeaters are unrelated to the matter, so it leaves us with the NIC and Layer 2 switch. D and E are correct.

9. On a local area network, one workstation can send data on the line while it is receiving data. What type of data transfer does this describe?

A) hybrid
B) half duplex
C) full duplex
D) multilink

Explanation: This is a full-duplex communication since both devices can transmit and receive simultaneously. C is the correct answer.

10. Refer to the exhibit. The small office network shown in the exhibit consists of four computers connected through a hub. Which configuration would cause collisions and errors on the network?

A) autonegotiation
B) FastEthernet
C) peer-to-peer shared resources
D) administratively configured full duplex

Explanation: D is the correct answer, since the device connecting the computers is a hub. We can not have an error-free network operating at full-duplex with a hub. If the device was a switch, it would be a different story.

11. Refer to the exhibit. The switch and workstation are administratively configured for full-duplex operation. Which statement accurately reflects the operation of this link?

A) No collisions will occur on this link.
B) Only one of the devices can transmit at a time.
C) The switch will have priority for transmitting data.
D) The devices will default back to half duplex if excessive collisions occur.

Explanation: Since full-duplex operation allows two devices send and receive information at the same time, there should be no collisions at all. The device is a switch (not a hub), so there should be no further problems. A is the correct answer.

12. Refer to the exhibit. All hosts are in listen mode. Host 1 and Host 4 both transmit data at the same time. How do the hosts respond on the network? (Choose two.)

A) Hosts 1 and 4 may be operating full duplex so no collision will exist.
B) The hub will block the port connected to Host 4 to prevent a collision.
C) After the end of the jam signal, Hosts 1, 2, 3, and 4 invoke a backoff algorithm.
D) Hosts 1 and 4 are assigned shorter backoff values to provide them priority to access the media.
E) If a host has data to transmit after the backoff period of that host, the host checks to determine if the line is idle, before transmitting.

Explanation: We know from the above article that when a collision occurs, a jam signal is sent and all devices invoke a back-off algorithm. After that time is up, hosts may then check the network for traffic. If it is open, the device may transmit. This describes answers C and E.

13. When a collision occurs in a network using CSMA/CD, how do hosts with data to transmit respond after the backoff period has expired?

A) The hosts return to a listen-before-transmit mode.
B) The hosts creating the collision have priority to send data.
C) The hosts creating the collision retransmit the last 16 frames.
D) The hosts extend their delay period to allow for rapid transmission.

Explanation: After the back-off algorithm is expired, all devices go bck to normal (listening before transmitting). A is the correct answer.

14. Which statement describes how CSMA/CD on an Ethernet segment manages the retransmission of frames after a collision occurs?

A) The first device to detect the collision has the priority for retransmission.
B) The device with the lowest MAC address determines the retransmission priority.
C) The devices on the network segment hold an election for priority to retransmit data
D) The devices transmitting when the collision occurs DO NOT have priority for retransmission.

Explanation: After a back-off sequence is expired, the devices that were in the collision do not have priority to transmit data. D is the correct answer.

15. Refer to the exhibit. A technician wants to increase the available bandwidth for the workstation by allowing the switch and the NIC on the workstation to transmit and receive simultaneously. What will permit this?

A) CSMA/CD
B) full-duplex
C) FastEthernet
D) crossover cable

Explanation: This is only applicable via a full-duplex connection, B is correct.

16. Why do hosts on an Ethernet segment that experience a collision use a random delay before attempting to transmit a frame?

A( A random delay is used to ensure a collision-free link.
B) A random delay value for each device is assigned by the manufacturer.
C) A standard delay value could not be agreed upon among networking device vendors.
D) A random delay helps prevent the stations from experiencing another collision during the transmission.

Explanation: This random delay helps prevent every computer on the network transmitting at the same time after the back-off algorithm is expired. Since it’s random for each device, collisions are unlikely. D is the correct answer.

17. In which two layers of the OSI model does Ethernet function? (Choose two.)

A) application
B) session
C) transport
D) network
E) data link
F) physical

Explanation: The bottom two layers of the OSI model deal with Ethernet functions-Physical and Data Link. Note that this is also the Network Access Layer in the TCP/IP model. E and F are both correct.

18. Which of the following are specified by IEEE standards as sublayers of the OSI data link layer? (Choose two.)

A) Logical Link Control
B) Logical Layer Control
C) Media Access Control
D) Logical Link Communication
E) Media Access Communication
F) Physical Access Communication

Explanation: Sublayers of the Data Link layer include Logical Link Control (LLC) and Media Access Control (MAC). A and C are both correct.

19. Where does the MAC address originate?

A) DHCP server database
B) configured by the administrator
C) burned into ROM on the NIC card
D) network configuration on the computer
E) included in the creation of the processor chip

Explanation: The MAC address is burned into the NIC at the factory- C is the correct answer.