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EIGRP errors

cro9uk
Level 1
Level 1

anyone ever seen this?

IP-EIGRP 10.4.1.10 not common subnet for E0/1

i am getting this on all interfaces of the 2600 router.

After some reading it appears that you only get these when you recieve EIGRP updates on your interface but from a different subnet. Checked the masks on all interfaces and are all correct.

Wan link is down (currently on ISDN backup) and telco say their point 2 point lease line is fine.

The router sees all interfaces as being UP UP but after clearing the ip cache it does not see any EIGRP learned routes. I tried a static but i get the following:

%inconsistent address and mask

this looks to me as though the router thinks the local addresses are on different subnets than the configured ones. No auto summary is configured, i'm left scratching my head.

Any help would be appreciated.

4 Replies 4

Harold Ritter
Cisco Employee
Cisco Employee

It looks like your interfaces could be inverted. Try a "show cdp nei" to make sure the correct neighbors are connected to the right interfaces.

The issue with the static route is unrelated. This message tells you that the prefix you entered is incompatible with the mask specified.

Hope this helps,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
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Cuauhtémoc, Juárez
Ciudad de México, 06600
México

Thanks for your reply. Wan link problem is sorted and was unrelated, i'm just very unlucky i suppose.

Could a hardware fault cause this? the reason i ask is because when i disconnect the voice card the errors cease.

I would think it very unlikely that a hardware issue caused the problem you describe about EIGRP neighbor not on common subnet. It would be very interesting to reconnect the voice card and see if the symptoms return. It would be helpful to have the output of show ip interface brief and show ip eigrp interface and show ip eigrp neighbor without the voice card and with the voice card.

If the symptoms do return if you reconnect the voice card then I would believe there is some software interaction between the software supporting the voice card and the software for the interfaces. In this case opening a TAC case would be the best thing.

HTH

Rick

HTH

Rick

After a little thought i have a theory, please tell me if i am right.

The voice card is not connected directly to the voice switch, the company who installed the telephone system connected to the voice card via my Cisco 2950 switch (don't ask me why). The voice card address has a 24bit mask whereas the LAN is on a 16 bit mask.

The lan uplink to the router is also on the 2950. Am i right in thinking that the router is advertising EIGRP on both interfaces, and therefore hearing each of them from the differing subnets (as they are both plugged into the the same switch)?

This would explain the errors and explain why the errors stop when i disconnect the voice card from the switch.

I think i am close.

Pete