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EIGRP continually flapping

pugs17211721
Beginner
Beginner

This is the message that I am getting from my 1941w router. I have a isakmp tunnel built with a GRE tunnel going through it. I keep getting the following message, continously.

Nov 16 08:58:09.352 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is up: new adjacency

Nov 16 08:59:47.361 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is down: Interface PEER-TERMINATION received

Nov 16 08:59:51.217 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is up: new adjacency

Nov 16 09:01:27.230 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is down: Interface PEER-TERMINATION received

Nov 16 09:01:27.782 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is up: new adjacency

Nov 16 09:03:03.792 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is down: Interface PEER-TERMINATION received

Nov 16 09:03:04.372 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is up: new adjacency

Nov 16 09:04:40.381 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is down: Interface PEER-TERMINATION received

Nov 16 09:04:40.909 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is up: new adjacency

Nov 16 09:06:13.774 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is down: Interface PEER-TERMINATION received

Nov 16 09:06:18.282 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is up: new adjacency

Nov 16 09:07:54.296 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is down: Interface PEER-TERMINATION received

Nov 16 09:07:58.436 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is up: new adjacency

Nov 16 09:09:29.521 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is down: Interface PEER-TERMINATION received

Nov 16 09:09:30.233 EST: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.20.255.97 (Tunnel31) is up: new adjacency

The other end of the device is a 2801 router and it doesnt show anything in the logs. Anyone have any ideas? Thanks.

1 Accepted Solution

Accepted Solutions

Sorry - I was referring to the tunnel transport MTU. Are all your physical links in between the two tunnels based on 1500MTU? If so....

You can first try using this on both sides under your tunnel interfaces (make sure that your physical interface is 1500, if it's Ethernet, the default should be 1500 unless it was globally changed).

Under tunnel interfaces:

 ip tcp adjust-mss 1376
 tunnel path-mtu-discovery

ip mtu 1400

 

You only need 1 of the last 2 commands but Cisco recommends putting them both...

Here's a good document although it's a bit 'lengthy' : http://www.cisco.com/c/en/us/support/docs/ip/generic-routing-encapsulation-gre/25885-pmtud-ipfrag.html

View solution in original post

31 Replies 31

cadet alain
Mentor
Mentor

Hi,

can you post output of following command:

debug eigrp packet

Regards.

Alain

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