North American Network Operators Group

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Re: That pesky AS path corruption bug...

  • From: John Fraizer
  • Date: Wed May 24 00:25:58 2000

On Tue, 23 May 2000, Vijay Gill wrote:

> > Since the corrupted AS-path does not include the AS that the route is
> > coming from (at least in the corruption that I saw) it seems to me that a
> > simple solution for all is to filter on AS i.e. only allow routes that
> > have the AS of your EBGP neighbor prepended to them.  I realize this does
> > not cover all cases of wacky AS corruption problems but it may fix some of
> This is a hack.  We do not need more cruft added on, rather, what we need
> is correct behavior.  The correct behavior being - if you see a corrupt/ a
> malformed update from a peer, send a notify and drop the session.  Seems
> fairly simple to me. 
> The above suggestion of your fails in case of route servers.
> Insist on correct behavior, not on cruftery.
> /vijay

Come on people.  It's VERY easy to do one of the following:

(1) NOT implement AS-path filtering on route-server connections
(2) Apply filtering on RS sessions with an as-path access-list that
includes those AS's that you will see via that RS.

Am I the only RA that notifies the peering contacts of all other RS peers
when someone new joins?  I certainly hope not.

John Fraizer
EnterZone, Inc