nanog mailing list archives

Re: AS prepending


From: Pete Templin <petelists () templin org>
Date: Fri, 08 Apr 2005 10:35:40 -0500


Philip Lavine wrote:

Update:

I am prepending my AS 3 times to the un-preferred ISP.
Both ISP's are my peers. The un-preferred ISP claims
the see my advertisement yet they do not add it to
their routing table (suggests filtering??). They claim
all the filtering they are doing is based on the
networks I told them over the phone that I was using
with that AS.

I have heard of providers who filter on AS path, and filter in such a way that more than N prepends (for varying values of N) causes the route(s) to be rejected. This could potentially be your problem. If they do soft-reconfig in on their customer sessions, they may see the route but filter it out.

pt


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