GRE Tunnel on Primary and secondary IP

Unanswered Question
Mar 11th, 2008


We need to form two GRE tunnels on a primary and seconadry ip address of ethrenet of 1841 router. We have given primary IP address as say a.b.c.d

and secondary ip as say p.q.r.s ( from different subnets ). Can we have tunnel interface 100 for primary ip address as source (a.b.c.d) and can we have tunnel inteface 200 for secondary ip address p.q.r.s as source . So that we will have two diferent tunnels for two seperate destination locatios.

Any link of

Thanks in advance


I have this problem too.
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Richard Burts Tue, 03/11/2008 - 09:07


I have not tested this and can not say for sure. But I suspect that it will not work well to configure a GRE tunnel to use the secondary address as source. In my experience when a router that has primary and secondary address builds a packet it will use the primary address as the source address and not the secondary address.

I believe that you can accomplish what you want without needing the secondary address. I have configured many routers with 2 GRE tunnels to different destinations using the same address as source for both tunnels. This works very well. As long as the tunnels have different destination addresses they can have the same source address and it is fine.




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