RE: BGP regular expression

From: Plank, Jason (JPlank@concordefs.com)
Date: Mon Aug 07 2006 - 18:00:31 ART


ip as-path access-list 1 permit ^300$

This regular expression will permit routes originating from 300, with only
300 in the as path. For instance, if you have a route 10.1.1.0 /24 with an
as path of 300 and 10.2.2.0/24 with an as path of 300 200 100 (or just 300
200) it would not match the as-path list.

$ denotes the end (or beginning, depends how you are looking at it) of a
line. _ means that digits can follow, so ^300_ would match 300 200 100.

I had a good link for regular expressions, I'll see if I can dig it up.
-------------------
Jason Plank, CCIE #16560
Network Engineer
101 Bellevue Parkway
Wilmington, DE 19809
E-mail: JPlank@concordefs.com
Phone: 302-793-5913

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
spycharlies@hotmail.com
Sent: Monday, August 07, 2006 4:43 PM
To: ccielab@groupstudy.com
Subject: BGP regular expression

Hey Guys

I was wondering wat the differences btw these 2 commands are, they seems to
be doing thesame thing (* prefixes learned from AS300)

ip as-path access-list 1 permit ^300_

and

ip as-path access-list 1 permit ^300$

cheers
Uyota



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