From: ccie2be (ccie2be@nyc.rr.com)
Date: Wed Feb 23 2005 - 23:03:01 GMT-3
No, they aren't the same.
The caret means start of string. Therefore, only 65109 can be matched.
The underscore means blank and some other stuff - I forget. So, the
difference is that with _65109$ your as-path filter will match all paths
where 65109 is the originating AS. So if the as path looks like this:
100 200 65109 matches ip as-path access-list 6 permit _65109$
200 65109 matches ip as-path access-list 6 permit _65109$
65109 only matches ip as-path access-list 5 permit ^65109$
HTH, Tim
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
mgrenham@eircom.net
Sent: Wednesday, February 23, 2005 8:43 PM
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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