BGP Path Filtering

Sean Donelan sean at
Sat May 17 00:10:22 UTC 2003

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.

More information about the NANOG mailing list