lab problem !!!!!

Unanswered Question
May 28th, 2007

Hey guys am failing to ping on my home routers. I have set the IP addresses correctly and rip is used on all the networks. The interfaces are up and running and when I use show cdp neighbors command, I can see the next routers but cant ping them. Does anyone know what am talking about and where am going wrong?

I have this problem too.
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mohammedmahmoud Mon, 05/28/2007 - 11:06


Since you can see your devices via CDP (CDP is a layer 2 technology) then the layer 2 connectivity is fine, thus it is probably a layer 3 IP problem, can you please paste "show ip route" from all your routers.

HTH, please do rate all helpful replies,

Mohammed Mahmoud.

bwgray Mon, 05/28/2007 - 11:42

If you can send the configs - alter your IP's though, don't post as they are.

vmzyece1977 Mon, 05/28/2007 - 12:29

google#sh cdp nei

google#sh cdp neighbors

Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge

S - Switch, H - Host, I - IGMP, r - Repeater

Device ID Local Intrfce Holdtme Capability Platform Port ID

yahoo Ser 0 146 R 2500 Ser 0

verizon Eth 0 145 S I WS-C2950-2Fas 0/1

cisco Ser 1 138 R 2500 Ser 1


vmzyece1977 Mon, 05/28/2007 - 12:31

google#sh ip rou

google#sh ip route

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area

* - candidate default, U - per-user static route, o - ODR

P - periodic downloaded static route

Gateway of last resort is not set is subnetted, 3 subnets

C is directly connected, Ethernet0

C is directly connected, Serial0

C is directly connected, Serial1


vmzyece1977 Mon, 05/28/2007 - 12:33


Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to, timeout is 2 seconds:


Success rate is 0 percent (0/5)


I cant understand why ping is not successful when cdp can work.

mohammedmahmoud Mon, 05/28/2007 - 12:36


What are you using for connectivity between the serial interfaces (is it just DCE-DTE cable) and can you please make sure that you don't have an ACL list.


Mohammed Mahmoud.

vmzyece1977 Mon, 05/28/2007 - 13:27

I just use the DTE-DCE cables, yes ,and there are no access lists watesoever.

Thank you for your quick post.


mohammedmahmoud Mon, 05/28/2007 - 13:32


You are very welcomed :), can you please post "show ip route" from ALL routers, and if applicable also the configuration, it should be a routing problem thus lets see.


Mohammed Mahmoud.

delatobanoah Mon, 06/04/2007 - 21:20

Can you ping the interfaces on the router itself? Also you said you are using rip yet there are no routes learned via rip in the routing table. It is kind of hard to tell what the problem is without the config.

danielyusuf Tue, 06/05/2007 - 01:30

if you are using back-to-back serial connection, please ensure that one router is acting as DTE and another as DCE. AFAIk, they can't work if both are DCE or both DTE

For a router acting as DCE, please entry clock rate 56000 under interface serial configuration. you can change the value 56000..



mukendi Tue, 06/05/2007 - 01:40

The problem is apparently from L3 to L7:

-RIP is a classful, use only default mask

-Check the IP address and the subnet mask

-Check for any ACL configured


c-ivan Wed, 06/06/2007 - 22:12

Hi there,

RIP is a classful routing protocol and as you are using 10.X.X.X addresses it will automatic summarize it to

To solve the issue, either choose RIP Version 2 and enter the command no auto-summary or use another routing protocol like EIGRP or OSPF.


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