[nsp] IP-EIGRP: Neighbor A.B.C.D not on common subnet...

[Yuval Ben-Ari]

Hi,

Not sure I understand your question,
the complaining router has 2 intefaces to 2 different segements.
the router sending the hello packet has single interface to another
segment (not one of the above 2).
all the 3 segments has a common router connected to it (core router)
I suspect the router is relaying the hello, is it possible ?

Were you able to eliminate the problem in your case ?

Yuval.

PS
I found this doc: http://www.cisco.com/warp/public/103/15.html
but it does not explain how I see the hello from a router on different
Vlan.

> -----Original Message-----
> From: Thomas Renzy [mailto:thomas.renzy at veritas.com] 
> Sent: Monday, January 27, 2003 12:01 AM
> To: Yuval Ben-Ari; cisco-nsp at puck.nether.net
> Subject: RE: [nsp] IP-EIGRP: Neighbor A.B.C.D not on common subnet...
> 
> 
> Yuval,
> 
> Do you have an EIGRP neighbor on this segment with a 
> secondary interface
> configured? I've seen this type of message when, on an 
> Ethernet segment, an
> EIGRP neighbor has a secondary interface configured on one 
> router, but not
> on another router on the same Ethernet segment.
> 
> EIGRP hello packets have a TTL of 2, so I don't think it 
> traverse the next
> hop. 
> 
> Thanks,
> Thomas Renzy 
> IS&T Global Network Services
> VERITAS Software
> Office: +650-527-4734
> Mobile: +650-996-7048
> Fax: +650-527-2034
> 
> "Some people drink from the fountain of knowledge, others 
> just gargle." -
> Author Robert Anthony
> 
> 
> 
> -----Original Message-----
> From: Yuval Ben-Ari [mailto:yuvalba at netvision.net.il]
> Sent: Sunday, January 26, 2003 3:11 AM
> To: cisco-nsp at puck.nether.net
> Subject: [nsp] IP-EIGRP: Neighbor A.B.C.D not on common subnet...
> 
> 
> Hi,
> 
> I noticed messages of the above kind while logging to a router and
> issuing 'term mon':
> 
> Jan 26 13:01:59.566 IST: IP-EIGRP(Default-IP-Routing-Table:1680):
> Neighbor A.B.C.D not on common subnet for FastEthernet0/0
> 
> Obviously the message means the router is seeing EIGRP hello packets
> coming on the interface from a neighbor which is not on that 
> interface's
> subnet, which happens to be correct.
> However I have no idea how these packets get to the interface as it is
> not on the same L2 segment (different VLAN).
> The error is only reported on terminal and not on all routers 
> (seems to
> be IOS dependent + 'eigrp log-neighbor-warnings' command)
> 
> Is it possible the hello packet is transiting a L3 device ?
> 
> Will be happy to hear your ideas.
> 
> Thanks.
> 
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