From: Nick Shah (nshah@xxxxxxxxxxxxxx)
Date: Tue Jul 09 2002 - 21:59:38 GMT-3
Robert
In the ip as-path access-list command, the carat (^) starts the input string
and designates "AS" and $ signifies the end of string. so essentially ^$
would signify "prefixes originated from this AS, and hence empty string"
In your case permit ^$ means "permit routes from this AS only"
permit .* means "permit all routes/all ASs"
deny ^$ means "deny prefixes originated from this AS"
same way deny .* would mean "deny all prefixes from any/all AS"
rgds
Nick
----- Original Message -----
From: "Robert Yee" <robert@bluespud.com>
To: <ccielab@groupstudy.com>
Sent: Wednesday, July 10, 2002 9:50 AM
Subject: Regular expression
> Hi all,
>
> Am I correct in my interpreation of the following regular expressions?
>
> .* = everything
> ^$ = nothing
>
> If the above is true, and I have the following in place:
>
> neighbor x.x.x.x filter-list 1 out
>
> ip as-path access-list 1 permit ^$
>
> Does this mean, that I am filtering all outbound prefixes?
>
> TIA,
>
> Robert
This archive was generated by hypermail 2.1.4 : Sat Sep 07 2002 - 19:36:24 GMT-3