> All big ISP has AS path filtering based on internet registries. They
> generate filters automatically one or two times in each day. Look at
> http://www.irr.net/ for example.

This is incorrect.

Most networks [this thread was about networks such as AS 3561,
701, 1, and 1239] of that sort employ some sort of filtering
towards peers that are also 'like them' in size or scope-- but
some don't do any filtering of inbound announcements other than
for bogons.

These policies, and the processes that get the actual filters
changed, are quite different from network to network.

These policies and processes for 'peer' connections are also
typically quite different than the policies and processes used
for customer connections.

Search the NANOG archives for RADB or IRR for more details and
a variety of opinions as to their usefulness.  You will also
find a good bit of information relating to how the major
networks employ various types of filtering across their 'peer'
and customer BGP sessions.

- jsb


-- 
Jeff Barrows, President
Firefly Networks
http://FireflyNetworks.net
+1 703 287 4221 Voice
+1 703 288 4003 Facsimile

An Advanced Internet Engineering
& Professional Services Organization



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