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New Member

GRE Tunnel

Hi All,

Currently we have the GRE tunnels backing up the frame-relay between our remote offices. The problem is that once the GRE tunnels are eastablished and EIGRP traffics are being passed, the GRE tunnels are going up and down.

  • Other Network Infrastructure Subjects
3 REPLIES
Bronze

Re: GRE Tunnel

It is difficult to make any real diagnosis with the information you have provided however, initially, I suggest you check out the IP reachability between your tunnel source and destination by doing continuous pings. If you have flapping routes in your network, it will be causing just this sort of behaviour.

Cisco Employee

Re: GRE Tunnel

tunnel will go up and down if you have recursive routing.

In other words, make sure you don't learn tunnel source and destination ip addresses from the tunnel itself (this would create recursive routing).

Use distribute-list to prevent advertising and receiving these routes.

New Member

Re: GRE Tunnel

If the tunnel works for about 10 seconds, and then goes down, it is probably an incorrect eigrp network statement. Be vary careful which networks you advertise.

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