CCNA EIGRP LAB Question
Question
After adding R3 router, no routing updates are being exchanged between R3 and the new location. All other inter connectivity and Internet access for the existing locations of the company are working properly.
The task is to identify the fault(s) and correct the router configuration to provide full connectivity between the routers.
Access to the router CLI can be gained by clicking on the appropriate host. All passwords on all routers are cisco.
IP addresses are listed in the chart below.
| R1 Fa0/0: 192.168.77.33 S1/0: 198.0.18.6 S0/1: 192.168.60.25 S0/0: 192.168.36.13 |
R2 Fa0/0: 192.168.60.97 Fa0/1: 192.168.60.113 S0/0: 192.168.36.14 |
| R3 Fa0/0: 192.168.77.34 Fa0/1: 192.168.60.65 Fa1/0: 192.168.60.81 |
R4 Fa0/0: 192.168.60.129 Fa0/1: 192.168.60.145 S0/1: 192.168.60.26 |
Answer and explanation
(Note: If you are not sure how EIGRP works, please read my EIGRP tutorial: http://www.9tut.com/eigrp-routing-protocol-tutorial. Note: You can download this sim to practice here: http://www.9tut.com/download/9tut.com_CCNA_EIGRP_sim_question.zip)
We should check the configuration of the new added router first because it does not function properly while others work well. From the command line interface of R3 router, enter the show running-config command
From the output above, we know that this router was wrongly configured with an autonomous number (AS) of 22. When the AS numbers among routers are mismatched, no adjacency is formed.
(You should check the AS numbers on other routers for sure)
To solve this problem, we simply re-configure router R3 with the following commands:
R3>enable (you have to enter cisco as its password here)
R3#configure terminal
R3(config)#no router eigrp 22
R3(config)#router eigrp 212
R3(config-router)#network 192.168.60.0
R3(config-router)#network 192.168.77.0
R3(config-router)#no auto-summary
R3(config-router)#end
R3#copy running-config startup-config
Check R1 router with the show running-config command:
Notice that it is missing a definition to the network R3. Therefore we have to add it so that it can recognize R3 router
R1>enable (you have to enter cisco as its password here)
R1#configure terminal
R1(config)#router eigrp 212
R1(config-router)#network 192.168.77.0
R1(config-router)#end
R1#copy running-config startup-config
Now the whole network will work well. You should check again with ping command from router R3 to other routers!
Modifications:
Maybe in this EIGRP Sim you will see the “passive-interface …” command somewhere in R1 configuration. If the link between R1 to R2; or R1 to R3; or R1 to R4) routers has the “passive interface” then we have to remove it with the “no passive-interface …” command because it prevents EIGRP update from being sent on that interface. But if the “passive interface” is applied to the link between R1 and ISP router like this:
R1:
!
router eigrp 212
passive-interface s1/0
!
then we just leave it. Don’t use the “no passive-interface s1/0″ on R1 because the link between R1 & ISP doesn’t need EIGRP to run on it. A static route from R1 to ISP & “ip default-network” command in R1 are correct so that all the routers (R1, R2, R3, R4) can access the Internet.
(Note: The “ip default-network” command in R1 will advertise the static route of R1 (to go to the Internet) to other routers (R2,R3,R4) so that they can access the Internet too). In the exam you will see these lines in R1 configuration:
!
ip default-network 198.0.18.0
ip route 0.0.0.0 0.0.0.0 198.0.18.5
!
If you want to learn more about “ip default-network” command please read: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094374.shtml
I read recent comments and realized that you will see the “passive-interface” in the link between R1 & ISP router so just leave it.
Note: Also some readers confuse about if we should use the wildcard masks on the “network” statements under EIGRP process or not. For example should we use:
router eigrp 212
network 192.168.77.0 0.0.0.3
The answer is: we can use wildcard masks or not, it does not matter. Not having a wildcard mask does not make the routes conflicting. The “network …” command in EIGRP (and OSPF, RIP) does not means “advertise this network” but means “If I has interface(s) belongs to this network please turn on EIGRP on that interface. Therefore when you don’t use wildcard mask EIGRP will turn on EIGRP on all interfaces that belongs to the network you specify in the “network …” command.
You should only use wildcard mask on EIGRP if you have 2 or more interfaces that belong to the same major networks but you don’t want to run EIGRP on all of them. For example if your router has 2 interfaces whose IP addresses are 192.168.30.1/28 and 192.168.30.17/28 but you only want to run EIGRP on the first interface, you can type “network 192.168.30.0 0.0.0.15″ under EIGRP process.
Other lab-sims on this site:
CCNA Configuration SIM Question (RIPv2 SIM)
U will enta d router eigrp command first ….
R1#router eigrp 20
R1(config-rtr)# is on d u will enter “no passive-interface se0/1
R1#router eigrp 20
R1(config-rtr)# no passive-interface se0/1
ok thanks!
@Michael
It was very similar. The only difference was the name of the eigrp network & the passive-network
@ebemusty
You would do it on the eigrp even though the passive-interface was attached to the se0/1?
why remove the passive-interface if it’s on se0/1 and not on Fe0/1…it doesn’t matter if it’s on the link to the ISP…it matters if it’s on the link to the R3 router or to one of the other routers
well i am not sure…. there was something keeping everything from communicating…. i believe the passive-interface was connected on R1… the passive-interface is the only reason i can think of that it wasn’t communicating… the eigrp was pretty similar to 9tut… instead eigrp 22 ..you had to change it to eigrp 2….
@cold
Yes That looks exactly like my lab but mine had a passive interface on the perimeter router… i believe
how does the passive-interface change the lab? is there another command that needs to be entered and if so where are you adding it? thanks
@ Jeff
You were able to advertise the network from R3 to R1, right?
@cold
What do you mean by advertise the network?
@ Jeff
you need to advertise that network since its not on R1
R1(config)#router eigrp 212
R1(config-router)#network 192.168.77.0
R1(config-router)#end
@cold @jeff
I need help I am taking the exam tomorrow..
on R3 in the output shown the router EIGRP is 22..
So will my command always be no router eigrp 22 (meaning whatever the EIGRP is command will be no router then the number?
Please help me out..
Michael – yes…you need to remove the incorrect eigrp AS – and reconfigure it to be the same as on R1
if it’s 222 on R1 – it needs to be 222 on R3 – so they can “talk” to each other.
so yes..the no router eigrp XXX will remove the eigrp, and then…
router eigrp XXX (the correct one to match with Router R1)
@cold
Yes i did advertise it…. after i did that… i couldn’t get the two remote routers to talk with the perimeter router…. on the two remote routers… you could run show commands but you couldn’t run config t or anything….it look like this
interface Serial1/1
no ip address
shutdown
!
interface Serial1/2
no ip address
shutdown
!
interface Serial1/3
no ip address
shutdown
That’s where i left it….. there was a passive-interface that i assume was keeping things from progressing any further… i couldn’t get it removed….
@ Michael
Just to add on Bar, remember to add back the Network on R3.
R3(config)#router eigrp 212
R3(config-router)#network 192.168.60.0
R3(config-router)#network 192.168.77.0
R3(config-router)#no auto-summary
R3(config-router)#end
R3#copy running-config startup-config
and Advertise the route 192.168.77.0 on R1 since it’s not listed there.
R1(config)#router eigrp 212
R1(config-router)#network 192.168.77.0
R1(config-router)#end
R1#copy running-config startup-config
Hope this helps.
Good luck on you exam tomorrow!
And tell us how it goes.
@michael
you will need to study on passive-interfaces….you might see them on the eigrp… on the ACL2 lab study possible modifications because it will more than likely be different from the one of 9tut a little bit… please let me know if the labs are different & in what way… i am going to re-test here in a few weeks….
@ Jeff
I’m out of ideas right now on what happened to that passive interface issue that you encounter during your exam. I did try to simulate it, I put the passive interface on Serial 1/0 which is connected to the Internet router. I never remove it and it never affected the traffic in any way. I can ping R1 and the other 2 routers.
Good Luck on your exam next week Jeff!
Do let us know how it goes.
@Jeff
For the ACL Sim1 (ACL SIMLET)
was it the same as on 9tut?
Just run two commands and then answer the questions at the end?
So on the EIGRP sim, if I cahnge the AS number on one router I need to change it on the rest of the routers to talk? Am i reading this right? I never seen this on the site. Any help would be really great.
Brandon – the other routers already work with the correct AS.
just R3 which was added last was configured with the wrong AS.
so in order for it to “talk” with the others – you need to fix its wrong AS.
@tommy
yes it was the same!!!
@cold
I know… I am out of ideas too… I am going to study the stuff on examtut.com plus focus on passive-interface…. if you can think of anything else let me know
Has anyone had the passive interface on their exam? If so how will I fix this?
Thanks Bar!
Does anyone know if the VTP sim still shows up on the test? I heard VTP is being repalced with ACL1 is this true?
I saw the passive interface during my exam. It is at Se 1/0 and is connected to the ISP router. If you saw that on your exam, you don’t need to do anything with it. As long it’s connected to the ISP router. But if it’s connected to the other router then that’s when you need to remove it.
conf t
router eigrp 212
no passive-interface (Name)
exit
Hope this helps
Hello,
For the CCNA exam, are you aloud to skip the sims and answer the questions first then complete the sims at the end?
Help me out, I want to finish my questions first then focus on the sims.
Can anybody confirm?
No you’re not allowed to skip a question. If you hit next without answering the question you’ll get no points to that question and you can’t back to answer it.
plz tell me how to configure passive interface in eigrp …..in real exam
if problem in passive interface in real exam soo how to solve problem in eigrp
any one
@malik: We have explained this in detail:
If the link between R1 to R2 (or R3, r4) routers has the “passive interface” then we have to remove it with the “no passive-interface …” command because it prevents EIGRP update from being sent on that interface. But if the “passive interface” is applied to the link between R1 and ISP router then we just leave it. Don’t use the “no passive-interface s1/0″ on R1 because the link between R1 & ISP doesn’t need EIGRP to run on it
Hello Admin I couldn’t open this EIGRP lab by packet tracer (5.3.1). Please suggest me how can
i open it.
Thanks,
Enayet.
@9TUT
How do you remove the passive interface?
How can you check to see if it is between R1 and ISP or the other routers?
thanks a lot but how to check that interface is passive or not
@9tut
what if the router number from R3 is correct?
@Mohammad Enayet Karim
I had the same problem. You need a few version of packet tracer or you the to a EIGRP file created with packet tracer 5.3.1 or below… i believe…. everyone can correct me if i am wrong….
@Mohammad Enayet Karim
To open the file you should have packet tracer 6.0.1, which is available on the link below.
https://docs.google.com/file/d/0B4CjGsNlfXWyRXUwSnNCT2pUT2M/edit
why the host or p.c can’t access or ping the isp router ??? urgent
asap.thanks in advanced
For this sim on the actual exam what will be the name of the mismatched AS instead of EIGRP 22?
hey guys.
i’m using packet tracer for this sim.
when i add default network 0.0.0.0 on R1 with the default route 0.0.0.0 0.0.0.0 198.0.18.5
R2 and R3 and R4 – can’t ping 198.0.18.5 (the iSP)
only when i add under router eigrp 222 – redistribute static – only then the routers can reach the isp router
what can be the problem? it supposed to work either way
also…you can just add the ISP’s network – 198.0.18.0 to R1 router eigrp even without the default route – and it will be advertised to the other routers – so there will be connectivity between them…so why use the default route at all?
How can you ping to check to see if they are working right?
i had passed my ccna exam with 972/1000 score on 12 feb.
the labs were acl1,acl2 and eigrp
acl 1 (same as it is)
eigrp (just change od AS and advertising a network (same as it is) with NO issue about passive interfaces and default network )
acl 2 (with bit modification)
“The task is to create and apply a numbered access-list with no more than three statements that
-> will allow ONLY host A web access to the Finance Web Server.
->All other traffic from A to finance server is denied.
->All traffic from lan servers(B,C,D) and core to the Finance Web Server is denied.
-> All other traffic is permitted to public server.
mikle, you can ping 198.0.18.5 (which is the isp’s address) from R2,R3,R4 – if you can ping – they are working right – if not – you have to use one of the methods above.
On the exam instead of Eigrp 22 what will it be called?
hi what command will show the passive-interface?
does anyone know how much the lab’s count on the ccna exam? I am talking point wise.
nevermind… i found what i was look for under FAQS
jeff , i listened that each lab contain 100 marks