nanog mailing list archives
Re: BGP Path Filtering
From: Brian Wallingford <brian () meganet net>
Date: Thu, 15 May 2003 23:16:28 -0400 (EDT)
I'd probably err on the most cautious side and use strict inbound prefix filters, only using outbound as-path filters toward upstreams as a sanity check. Unless you're a legacy peer with large networks, chances are you'll be expected to arrange for acl mods with your peers/upstreams to propagate your clients' announcements anyway. hth, Brian ps - you're correct - there doesn't appear to be a BCP. Common sense, tempered by a healthy dose of skepticism regarding one's clients' competency would seem to steer the solution :) On Thu, 15 May 2003, Mark Radabaugh wrote: : :I'm having a hard time finding best practices for filtering outbound bgp :announcements when providing transit to bgp-speaking customers. While we :currently multi-home to several providers it appears we will soon need to :provide transit for customers with their own AS's. : :I find lots of references (and understand) the basic : :ip as-path access-list 3 permit ^$ : :and it would seem that should we wish to provide transit for a bgp customer :AS12345 we would use: : :ip as-path access-list 3 permit ^12345$ : :but I think this breaks if AS12345 prepends their advertisement. : :Next up is: : :ip as-path access-list 3 permit ^12345_[0-9]$* : :Which seems correct to me. Is this still best practice (or even correct)?
Current thread:
- BGP Path Filtering Mark Radabaugh (May 15)
- Re: BGP Path Filtering Brian Wallingford (May 15)
- Re: BGP Path Filtering Jay Ford (May 15)
- Communities BCP [was: RE: BGP Path Filtering] Deepak Jain (May 16)
- Re: Communities BCP [was: RE: BGP Path Filtering] Daniel Golding (May 16)
- Re: Communities BCP [was: RE: BGP Path Filtering] Joe Abley (May 16)
- Re: Communities BCP [was: RE: BGP Path Filtering] Jay Ford (May 16)
- Re: Communities BCP [was: RE: BGP Path Filtering] Danny McPherson (May 16)
- Re: Communities BCP [was: RE: BGP Path Filtering] Stephen J. Wilcox (May 16)
- Re: Communities BCP [was: RE: BGP Path Filtering] Danny McPherson (May 16)
- Re: Communities BCP [was: RE: BGP Path Filtering] Richard A Steenbergen (May 16)
- Re: Communities BCP [was: RE: BGP Path Filtering] Guy Tal (May 16)
- Communities BCP [was: RE: BGP Path Filtering] Deepak Jain (May 16)