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)
Hi everybody. Passed today 881/1000. Sims were ACL2, EIGRP, VTP. Basic drag&drop, IOS commands. Mainly STP, VLAN, VTP questions. Also NAT and IPv6. Sekhar dump at examcolletction is valid but not all questions are in the same form in the real exam.
Good luck everybody.
Pls my Good friends can anyone send me the full version of VCE CONVERTER, at : lordschosen81@yahoo.com
its 50 questions include 3 lab. Lab is ACL2 , Eigrp and vtp.
I pass my exam on 3rd oct wit 920/100 .. Thanks 9tut and friends for your help .
hi,please someone can tell me what has changed in the eigrp sim(ip adress,name of R3,AS or the scenario?)thanks
I just took my ccna today and the EIGRP Process ID was 23. The interfaces on the New router that was added and the connecting upstream router were Fa0/0 on both ends. the IPs were 192.168.36.13/30 upstream and 192.168.36.140/30 on the downstream (new router) The existing router had the wrong AS number, it had AS22 and it did not have the IP subnet in the existing EIGRP configs.
i have a doubt about passive interface ?
where is it located ? how to ENABLE OR DISABLE IT?
i will be thankful anyone who hels me out .
if u can give a example it will be more worthy .
hello,someone can tell what are exactly changed on the exam’s sims(eigrp,acl and vtp)? I have my own thursday please
@9tut
@EIGRP SIM. This SIM was in the exam today. Im confident I completed this SIM correctly. I rightly did my “no auto-summary” and saved my work, after I’ve changed the “autonomous number” on “server router” and added the missing network address on the other. And I did get my adjecencies alright. Yet I got 54% for this SIM.
One thing I noticed was that the Router directly connected to the internet had a “Passive-Interface” on the 1st line and all the network addresses came under that line. However when you do a “sh run” the “passive-interface” was only directed at the interface connected to the ISP Router. So I just left it as it was.
What could I have missed?
Hi everyone,
has anyone taken their exam recently. Does the LAB Sim change? or is it still the same(eigrp,vtp and ACL)
Hi Does anyone know if the tab key works in the sims? and the ? mark key i take it is allowed yes?
@9tut and @All
In EIGRP Simulation Routers have IP address with different subnet mask like(255.255.255.240 and 255.255.255.252). But your downloadable simulation has same subnet mask like (255.255.255.252) for all IP address. Is that occur any problem in real CCNA exam???
Wait for suggestion. I am taking exam on 18 Oct.
@9tut
Please reply for Eugene’s question?
If EIGRP doesn’t configure with
passive-interface serial1/0
and
ip default-network 198.0.18.0
ip route 0.0.0.0 0.0.0.0 198.0.18.5
should i configure them??? or leave it??
@Arif
No you don’t have to configure it, just read what they are asking for.
@Eugune
You may think that you saved it. You MUST ping first from etch router to check if connectivity is fine, check for extra and unwonted network statement, it was on my exam on router connected to ISP, if it is present – remove it. then save config on BOTH routers.
@Mike
Surely, there was an unwanted network on Router connected to ISP but I don’t see how that would affect adjencencies or connectivity. Like l said my adjencencies formed alright. And am 100% I saved my work.
Can you chip in please 9tut
The previous comment was mine.
@Eugene: Yes, the unwanted network does not affect anything. We just remove it because it has no use. In fact we don’t need to remove but I am not sure if the simulator in the CCNA exam will reduce score or not. So we should remove it.
@Eugune
Who knows, maybe Cisco is checking you attention:) You are right, it will not effect but… Just in case better to remove.
@ everybody, when the problem description says: “Access to the router CLI can be gained by clicking on the appropriate host. All passwords on all routers are cisco.”, does it mean that we can get acces oONLY thru the PC connected to R1?? or can we click on any router to acess the CLI?? Im asking it because later it says that we need to modify the R1 by adding one more network and also R3, or can we just click on the PC1 and telnet or ssh to any other devices to check and make sure the proper settings??? I hope someone understand what Im asking… regards,
@alex: You just click on the relevant PC for gaining CLI (Command Line Interface) on the relevant router (see the console connection represented by a ‘dashed line’ for each router). For example, to gain access on R1 you need to click on Host G and the CLI opens automatically; for accessing R2 click on Host B (see dashed line – console connection), for accessing R4 click on Host F, etc.
The meaning of the console connection, is that you can access the router’s CLI directly even when there is no any IP address configured on the Router.
I passed my exam tomorrow please! give me the method to better handle sim (EIGRP, VTP, ACL)
thank you very much to all!
send me bachardaman@yahoo.fr
thank you all!
@paps
Please tell me what are changed if you finished your exam in eigrp labs and access-list lab.i have exam too in few days after you.
ok @herman !!!
@papson
please also tell about VTP question that isn’t here in 9tut. Thanks in advance.
@9tut
If I don’t see “passive-interface” in the link between R1 & ISP should I use the command
“no passive-interface” between R1 and ISP.
Please reply. I am taking my exam on 22 Oct.
Sorry i mean should I use the command “passive-interface” in the like between R1 and ISP on previous comment
is the ip default-network supposed to be 198.0.18.4 or 198.0.18.0
Hello. I did’t pass my exam yesterday. 788/1000
Why no passive-interface se0/0 does not work on R1-S0/1?. It show error at s from se0/0. Is it possible to erase the whole eigrp config on this router and recreate it?, this just to get rid of passive-interface.
Acl2 dind’t work despite same lines applied!!.
Anyway I will apply it again one month forward and try to study even more.
Somebody, some comment?.
@Cesar
Did you see “passive-interface” in the link between R1 and ISP? If “yes” or “no” what you did?
@Mike
Please comment on Ceser post. Why “no passive-interface” doesn’t work on both serial interfaces. Without doing “no passive-interface” on both serial interfaces we unable to do ping on those interfaces and router R1 never get information from those routers too.
Am I right?
@Cesar
Would you please tell me why ACL2 didn’t work. What was the objectives to do and you did what? If you can please post the codes too.
@Arif, Cesar
If passive interface was on s0/1 and you were trying to remove it from your comment on s0/0, it will be given you an error as it’s not applied on s0/0. Please pay good attention on exam, make sure you typing everything correct, and if you don’t this sing “^” giving you hint where you did mistake. And to remove passive-interface no need to erase all config, just “no” under EIGRP
@Mike
Thanks a lot.
Hello, Arif, thanks for your answers!.
EIGRP.
passive-interface was not between R1 and ISP, it was applied on se0/1 on R1 to R4, so I guessed I needed to get rid of it using no passive-interface se0/1 but did not work, nevertheless pings did work, I was explain already why pings worked, because passive-interface only avoids route updates traffic. But anyway no passive-interface se0/1 didn’t work for me.
ACL2.
Lab asked the following:
1. To allow web traffic from host D to Financial Web Server.
access-list 100 permit tcp host 192.168.33.4 host 172.22.242.23 eq 80
2. Deny all other traffic from host D to Finacial Web Server:
access-list 100 deny ip any host 172.22.242.23
3. Allow all other traffic:
access-list 100 permit ip any any
This using exam ip’s.
I realized 2nd. line is different than 9tut’s, but it is not suppose to work as well?, I mean to block web traffic to any host, and first line allow web access from host D. It should be the exactly the same on the exam than here in 9tut’s?.
I put this in 2nd.: access-list 100 deny ip any host 172.22.242.23
9tut’s: access-list 100 deny tcp any host 172.22.242.23 eq 80
Is not the same?. I tried and web access did not work from host D, nor another host on that LAN. But I guess form host D should have worked because of the first line.
Another thing is that I did not finished reading the lab, so I first put 4 lines on the ACL and did work correctly, then when I finished reading, that’s when I had to change from 4 to 3 lines, cus they were asking to do it in 3 lines; If someone does it using 4 lines can gain some points or should be in 3 strictly to gain the points?.
Thanks in advance for your help.
I have like a month to redo the exam, so I am not finished yet, 1 more month to study and practice.
What are the odds that someone get the same labs for a second try in short time between 1st and 2nd tries?
@Cesar
1. Your first mistake:
2. Deny all other traffic from host D to Finacial Web Server:
access-list 100 deny ip host (ip of host D ) host ( ip of FWS)
In your config you denied all hosts from accessing FWS. Yes, it had to be only 3 statements. Other thing make sure you typing correct ip address, best option is to check 3-4 times before press ENTER.
And you are right about passive interface, it’s blocks only EIGRP updates sends out this interface, but if it is, no network updates will be send, so router 4 will lose all connectivity with router 2 and 3. It is all depends from where you were trying to ping. If from router 1 to 4 it will work, directly connected. From router 4 to router 2 will work, but to router 1, 3 and ISP it will not, no updates is coming to router 4.
From router 4 to router 1 will work, but to router 2, 3 and ISP it will not, no updates is coming to router 4.
Sorry, typing mistake, mixed numbers
Mike pls tell me, the access list given to cesar on which interface can i apply it and on what direction
@Cesar
You did mistake in ACL2 by blocking whole network to Finacial Web Server. It should be like this
access-list 100 deny ip host (ip of host D) host (ip of host FWS)
and Mike gives a really nice comment. Thanks @Mike for his valuable comments.
Thanks all, Mike, Arif.
All are valuable comments that would really help me in my next try, which is in about a month. Only doubt remains on my head is the question I asked some lines above: “What are the odds that someone get the same labs for a second try in short time between 1st and 2nd tries?”. Somebody knows?. This would help me to prepare at the very same labs or study some others.
plz tell me how to find the mask value of 192.168.77.33?
I did the exam yesterday and this question came out, but i want to ask that if u forgot to save your configuration, will it affecct your score or not, even if you did your configuration well? Because i failed the exam and i realized i didn’t save my configuration.
hi every one i’m finally going to take the exam on thursday 12 noon pls help in any way
These lines that 9tut coments that will come on R1:
!
ip default-network 198.0.18.0
ip route 0.0.0.0 0.0.0.0 198.0.18.5
!
would not they go like this?:
!
ip default-network 198.0.18.4
ip route 0.0.0.0 0.0.0.0 198.0.18.5
!
I think instead of publishing 18.0 network, should be 18.4.
Is this right or not?. I comment this because mask is 255.255.255.252, so network is 198.0.18.4, broadcast .7 and usable addresses would be .6(R1) and .5(ISP). By the way putting any 18.4 or 18.0 as the network, I can not ping 198.0.18.5 (ISP serial interface to R1) since R2, R3 and R4 routers. Why is this?.
Thanks!.
@Cesar
It is because your ISP doent have static route back to any of your network EIGRP topology.
You can configure it and then it will work
Thanks a lot @Mike!.
Yes you are right!!, I was missing that detail!!. I have to try it, but at a first glance do you think adding static route on ISP you mention it will work with 198.0.18.0 as the nerwork published usgin ip default-network command?, my logic tell me not because of the addressing scheme serials between R1 and ISP have, which is = /30 = 255.255.255.252, .4 = net, .7 = broadcast, .5 = first usable (and assigned to se0/1/0 from ISP to R1) and finally .6 = last usable (and assigned to se1/0 from R1 to ISP). I think besides publishing the static route on ISP router you mentioned, the actual command should be ip default-network 198.0.18.4 instead of ip default-network 198.0.18.0 in order for pings to work from either R1, R2 or R3 to 198.0.18.5 which is the se0/1/0 interface from ISP router to R1.
Isn’t this correct, or anyway it should work usign 198.0.18.0?
Thanks a lot!,
Cesar.
Another thing I forgot!.
Pings from R1, R2 and R3 to ISP router se0/1/0 (198.0.18.5) should work on the exam in order for the lab to be correct?. Should we configure static route on ISP router in order for these pings to work?, if so I did not see any PC attached to ISP router to do so.
But can we even configure anything on ISP .. I do not think so.. We can configure only on other routers to the extent I remember …
when i took the exam the last time ,i blieve i did every think right
for ex:there was a wrong AS number of which i change,add network end did the no auto-summary comand, and finally go to router 1 en add the network no agacencies was formed.
can some one pls tell me what i am missing on the static route and eigrp
as i will do my exam 2morrow
if at all you will configure a static route on the isp router how can this be configure
pls help me with an example of such configuration
@Oct18
After adding the network on R1 did you type “no auto-summary”. Because without this command adjacency can’t formed and you can’t ping from newly added route(in this 9tut sim it is R3) to other routers(R1, R2, R3).