%IPRT-3-RIB_LOOP: Resolution loop formed by routes in RIB

[CSCO11777723]

Does someone know how to debug this error message please?

%IPRT-3-RIB_LOOP: Resolution loop formed by routes in RIB

This error message spread everywhere inside my network.

thanks!!

[Mohammed Imran Khan]

Hello Vincent,

This error mean that RIB route producers have installed routes in the RIB that form a loop during resolution. But, there could be several reasons for this. For. eg: a route received from a neighboring device and being installed in the RIB that conflicted with an already known/installed path.

When were these logs observed? Are there any other logs alongside this which can shed some more light on the actual problem. The supporting logs can tell which component is triggering this (like CEF discovering the routing for a prefix has recursive paths that lead back to itself). These logs are merely symptoms.

"show log" and "show ip route loops" will be good to have to start with!

Regards,

Imran

[christo russouw]

Spot on chang, I just got this in a lab and that was the solution :)

[ciscochang]

Could be a problem that the subnet of the point-to-point interface does not match.

i.e. a /24 on one side and a /30 on the other.

Just experienced a similar problem.

[Pradeep Thorat]

Really spot on . Just faced an similar issues and got it resolved. subnets were mismatched. Thanks.

[KHOROMBI MICHAEL]

Experienced the same isssue,  invalid p2p subnet mask.

[Mikheil Zhizhilashvili]

I had this problem when I make iBGP configuration without update-source/next-hop-self, 

there was very complex topology so I can't explain exactly reason. shortly there really was loop. 

sh ip route loops 

sh ip bgp rib-failure