BGP Path Filtering
Jay Ford
jay-ford at uiowa.edu
Fri May 16 04:23:30 UTC 2003
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 like using BGP communities:
o filter announcements you receive from downstreams based on your
criteria of choice
o set a specific BGP community (yourAS:whatever) on announcements which
are to be propagated to various places (upstream providers, etc.)
o do output filtering based on the communities you set
Make sure you clear yourAS:whatever in announcements from your BGP peers.
You can use this same technique for prefixes you originate, so that all your
outbound BGP filtering is based on communities.
________________________________________________________________________
Jay Ford, Network Engineering Group, Information Technology Services
University of Iowa, Iowa City, IA 52242
email: jay-ford at uiowa.edu, phone: 319-335-5555, fax: 319-335-2951
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