gre tunnel problem after router replacement

[PETER GEEBAUER]

Hi

We 've changed our router , so we replace the one with same IOS and configuration  but not all gre tunnel interfaces change their state to up.

in our head office and in our branch the tunnel interfaces states are down , so we delete the keepalives on interfeace headquater and branch office the tunnel protocol changes its state to up but there is no connection.

So we changed back to our old Router and it worked fine.

regards Peter

interface Tunnel1102
ip address xx.xx.xx.xx 255.255.255.252
ip ospf network point-to-point
keepalive 3 3
tunnel source xx.xx.xx.xx
tunnel destination xx.xx.xx.xx
tunnel key 1102

[Raphael Wouters]

Hi Peter,

The two reasons for a tunnel to be down is either that the tunnel destination is not on the routing table or -if you have keepalive- that they are not answered.

Since when you remove the keepalive the tunnel comes up, I believe there is a problem with those. Can you try to ping the tunnel destination with the source of the tunnel source? (ping xxxx source yyyy)

You can also use "debug tunnel keepalive" to check where or in what direction the keepalive are dropped based on the logs you may see on both routers.

What is common to the tunnels are down? Look at packet path, peer and interfaces used.

Also, are all the packets supposed to flow through the same interface? You can also already check for drops on that interface (show interface).

Thanks,

Raphael

[PETER GEEBAUER]

Hi Raphael

Thanks for your answer in this case.

we started yesterday a new troubleschooting session in this case and we found the failure,it was only a clear arp after router replacement and all the tunnels comes up

regards

peter

[Raphael Wouters]

Thanks Peter, I'm glad you found the solution!