From: Gustavo Novais (gustavo.novais@novabase.pt)
Date: Thu Sep 22 2005 - 06:31:10 GMT-3
Why not use ^123_[0-9]* instead of + and the extra line?
Since the * matches the chars 0 or more times, and the _ char is not
included within [0-9] that would match either ^123$ or ^123_456$ or
^123_65535$
If in doubt of your as-path list you can always do sh ip bgp regexp to
see what matches or not.
Gustavo
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
simon hart
Sent: quinta-feira, 22 de Setembro de 2005 7:45
To: Schulz, Dave; syv@911networks.com; Leigh Harrison
Cc: Cisco certification
Subject: RE: BGP Reg Exp
Dave,
this was the original answer that I gave:
The Reg Exp you are probably looking for is
^123(_[0-9]+)?$
Which transpires as
^ begins with 123
()? anything within the brackets can occur either no times or once
()?$ so now it will end with either 0 occurrence within the bracket or
one occurrence
[0-9)+ match 1 or more sequence of the numbers 0 to 9
Thus ^123(_[0-9]+)?$ will give you the directly attached AS and there
directly attached clients
A tip for when you doing the lab. The Doc CD has a section regular
expressions within the configuration guide, Part 1 Cisco IOS User Guide,
Using the Command-Line Interface
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/
ffun
_c/ffcprt1/fcf001.htm#1002051
HTH Simon
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Schulz, Dave
Sent: 22 September 2005 02:28
To: syv@911networks.com; Leigh Harrison
Cc: Cisco certification
Subject: RE: BGP Reg Exp
Leigh -
I didn't see a follow up on your question. But I believe that if you
want to have the AS123 and it's neighbors, you will need to two lines:
ip as-path access-list 1 permit ^123
ip as-path access-list 1 permit ^123_[0-9]+
Dave Schulz,
Email: dschulz@dpsciences.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
syv@911networks.com
Sent: Sunday, September 18, 2005 5:33 PM
To: Leigh Harrison
Cc: Cisco certification
Subject: Re: BGP Reg Exp
Leigh Harrison wrote:
> All,
>
> If I wanted to allow a neighboring AS(123) and his directly connected
> AS's to be seen as routes to me, could this be written as:
>
> ip as-path access-list 1 permit ^123_[0-9]*$
http://www.911networks.com/pages/cisco/bgp/regular-expressions.php
> OR
> ip as-path access-list 1 permit ^123_.*$ OR ip as-path access-list 1
> permit ^.+_[0-9]*$ OR ip as-path access-list 1 permit ^.+_.*$ OR ip
> as-path access-list 1 permit ^[0-9]+_[0-9]*$ OR ip as-path access-list
> 1 permit ^[0-9]+_.*$
>
> Could someone have a quick look and let me know if that would be the
> same thing ? I think I'm getting there!! The only niggle in the back
> of my mind is ^123_.*$ (for example), would I need a "+" after the 123
?
>
> Many thanks,
> LH
>
>
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