GRE tunnel works between routers, not external devices.

Unanswered Question
Jan 31st, 2007

Hi all,

I am trying to configure a GRE tunnel between two sites. In my configuration I have three Cisco routers. Router A and Router C are at the first site and are connected directly to each other - Router B is at the second site.

We can create the tunnel between Router A & B no problem. Running an show int tunnel 0 shows the link up. Router A can ping the interface on Router B and vice-versa. However I cannot ping the Router B interface from Router C. I feel like I am missing something basic but cannot identify it.

Relefant configuration and pings/traceroutes are available at the following URL.



I have this problem too.
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dominic.caron Thu, 02/01/2007 - 07:00

You need to add a router to router B

ip route tunnel 0

When you did your ping from router A To B, the source of the ping was the ip of the tunnel interface. It was a subnet directly connected to router B so no need for route.


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