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I'm getting lots of messages on a router

IGRP-IPv4:(50)(Default-IP-Routing-Table:50): Neighbor not on common subnet for Vlan11 doesnt respond and show ip route says is directly connected on Vlan1. This must be off one of the trunk ports but how can i find out which port this neighbor connects on so i can fix the problem?


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Looks like the subnet mask for the two Vlan interfaces doesn't match. What does sh run int vlan 11 say? Does it match the mask on that VLAN on other devices?

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yes they don't match - vlan 11 is Vlan 1 is So something is misconfigured with wrong ip address, but i can't see what it is or where it connects to be able to fix – Jude May 24 '11 at 14:24
interface Vlan1 ip address end interface Vlan11 ip address end – Jude May 24 '11 at 14:27
What are you trying to do? To establish EIGRP you need both devices on the same VLAN and the same subnet configured on the two devices. – HampusLi May 24 '11 at 14:35
I'm trying to see what device is wrongly configured so i can stop the error messages. I'm not sure if this error is causing any real problem, but i'd like to get rid of it. I guess some device is configured wrongly, but how can i track it. If i can get the MAC address somehow for the device i can track to an interface and then console on – Jude May 24 '11 at 14:37
Looks like you are mixing vlan 1 and 11? EIGRP will send a multicast request to discover neighbours. Again, you need the same VLAN and same subnet to establish EIGRP (if you actually need/want EIGRP on this vlan 1, if not just set it as a passive-interface in the EIGRP config. – HampusLi May 24 '11 at 14:52

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