BGP filtering for own AS number

Martin Barry marty at
Thu Jan 6 20:27:50 CET 2011

$quoted_author = "Ivo Smits" ;
> On the dn42 network ( we have been seeing quite
> a few BGP ghost routes lately. After some research, it turns out
> that bird may not correctly handle received AS-paths containing the
> own AS number. Bird ignores incoming BGP routes containing the local
> AS number - completely. This may result in an older, now invalid,
> route not getting removed.

This sounds like it's working correctly.

Bird is effectively ignoring the route with it's own AS in the path.

The older route will therefore not be displaced.

It would require a specific BGP withdrawal for the old route to go away in
this context.


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