nanog mailing list archives

Re: BGP Path Filtering


From: Sean Donelan <sean () donelan com>
Date: Fri, 16 May 2003 20:10:22 -0400 (EDT)


On Fri, 16 May 2003, Leo Bicknell wrote:
In a message written on Fri, May 16, 2003 at 08:00:00PM -0400, Sean Donelan wrote:
Large ISPS (more than 500 eBGP neighbors and 5000 prefixes) are going to

MFN / AboveNet qualifies as a "large ISP" by your definition, yet:

sufficient). ANS was the only major commercial provider I knew which
explicitly configured BGP announcement filters for every network prefix
from every source.  According to studies, about 70% of large ISPs

We prefix-list filter all of our customers.  We have from time to
time made an exception due to route limits, or people limits, but
we still exceed 99% of our customers are fully prefix-list filtered
on all inbound announcements.  It's not that hard.

I said *EVERY* network prefix from *EVERY* source.  I didn't limit it to
just customers.  ANS also filtered peers.





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