From: Keane, James (James.Keane@agriculture.gov.ie)
Date: Thu Feb 24 2005 - 09:24:41 GMT-3
Ollie
I believe it to be
^ beginning of string
$ end of string
_ does comma AND beginning and end (and brackets etc)
according to Cisco BGP-4 Command and Config Guide by William R Parkhurst
'^2$ is routes originated by neighbor AS2
^2_ all routes from directly connected neighbor in AS2'
so since you have
ip as-path access-list 5 permit ^65109$
ip as-path access-list 6 permit _65109$
If you had 65123,65109
5 wouldnt match and 6 would.
Whereas if you had a path of 65109 both work (but you would probably lose marks for access-list 6)
James
-----Original Message-----
From: mgrenham@eircom.net [mailto:mgrenham@eircom.net]
Sent: 24 February 2005 01:43
To: ccielab@groupstudy.com
Subject: as path filtering
Hi Group,
can anybody explain the difference between the below AS path filters. I understand that the _65109$ represents prefixes originated in AS 65109 but what about ^65109$ ?? Are they the same?
Ollie
ip as-path access-list 5 permit ^65109$
ip as-path access-list 6 permit _65109$
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