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New Member

Monitoring GRE tunnels


I would like to monitor GRE tunnel interfaces which are using the LOOPBACK address as the tunnel source & destination.

As the Loopback address is a logical interface and it never goes down so I dont know really if the link is down or up incase when in between router is actually down.

OR4 ---- OR3 ----- OR2 ----- OR1 ------ OR0

in the above example if OR2 is down then OR0 and OR4 will show the tunnels interface as UP and line protocol is UP but infact the link is not working.

Your help would be highly appreciated.

Thank you and Best Regards


  • Other Network Infrastructure Subjects
New Member

Re: Monitoring GRE tunnels


There's a fairly new feature called GRE keepalive that will solve your problem. Prior to this feature, GRE tunnels would show up/up as long the routing table had a route (static or otherwise) to the destination tunnel endpoint.

Here's a link to the feature:

Good luck.

New Member

Re: Monitoring GRE tunnels

Dear Masharris

Thank you for your response; I will check the Keepalive feature, but I was not able to check the above link because its asking for the password.

Would it be possible for you to send me the above article by email @ in PDF format.

Thank you.

Best Regards


New Member

Re: Monitoring GRE tunnels

Khan, do you have a login for CCO? That's the pw its prompting for, if not I'd be glad to send you the PDF.