AS path question.

Nick Olsen nick at
Wed Nov 10 14:31:58 CST 2010

They are prepending routes.
Looks like both 43022 are prepending, As well as 47359...Multiple times... They do this to make that route look "bad" so it comes in other transit they have.

Nick Olsen
Network Operations
(855) FLSPEED  x106


From: "Greg Whynott" <Greg.Whynott at>
Sent: Wednesday, November 10, 2010 3:23 PM
To: "nanog at list" <nanog at>
Subject: AS path question.

Recently I adjusted the maxas-limit option on our router,    logs started reporting routes being refused because the AS path is to long.   seems to work as expected.

when I looked at the logs I was a bit confused at what i was looking at...   why is it there are multiple AS's in the path that appear to be the same AS?  I expected an AS path comprised of mostly unique ASs.

instead of this:

476330: Nov 10 14:55:07.247 EDT: %BGP-6-ASPATH: Long AS path 549 26677 6939 21011 43022 43022 43022 43022 43022 47359 47359 47359 47359 47359 47359 47359 47359 received from isp router: More than configured MAXAS-LIMIT

i expected it would look more like:

476330: Nov 10 14:55:07.247 EDT: %BGP-6-ASPATH: Long AS path 549 26677 6939 21011 43022  47359 received from . .. .

thanks for your time again,


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