From: Armand D (ciscoworks2001@xxxxxxxxx)
Date: Wed Aug 21 2002 - 12:32:30 GMT-3
Here is what worked for me IOS 12.1......
I only what to accept BGP routes that originate in AS4
and any other possible autonomus systems directly
connected to AS4. All other BGP routes will be
filtered.
neighbor 10.1.1.254 filter-list 1 in
ip as-path access-list 1 permit ^4_[1-9]*$
HTH
Armand
--- Abidin Kahraman <kahramana@superonline.net> wrote:
> Is this ok ?
>
> ^1000_100(_.+_)10$
>
> I`ve tried on my router and it seems ok, what is
> your ideas?
>
> Abidin.
> -----Original Message-----
> From: Brian McGahan [mailto:brian@cyscoexpert.com]
> Sent: Wednesday, August 21, 2002 5:21 PM
> To: 'Brian McGahan'; 'elping'; 'Michael Snyder'
> Cc: steven.j.nelson@bt.com; ccielab@groupstudy.com
> Subject: regexp fun (was RE: Filtering BGP updates
> using ip as-path
> access-lists)
>
> Did we give up already?
>
> <snip>
>
> Try this one: All routes originated in AS 10,
> passed through AS
> 100, and learned from AS 1000. (In one line)
>
> HTH
>
> Brian McGahan, CCIE #8593
> Director of Design and Implementation
> brian@cyscoexpert.com
>
> CyscoExpert Corporation
> Internetwork Consulting & Training
> http://www.cyscoexpert.com
> Voice: 847.674.3392
> Fax: 847.674.2625
>
>
> -----Original Message-----
> From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com] On Behalf Of
> elping
> Sent: Sunday, August 18, 2002 9:46 AM
> To: Michael Snyder
> Cc: steven.j.nelson@bt.com; ccielab@groupstudy.com
> Subject: Re: Filtering BGP updates using ip as-path
> access-lists
>
> steve :
> consider that
> ^4 [0-9]* will be an exact 4 and some other number
> so any routes coming from 4 will not show up...
>
> i put your theory to the test on an actual Bgp
> routing table observ.
> I am using 7788 and all it's connected routes..
>
> in summary the underscore will allow 7788 routes and
> it's
> connected...without the underscore
> you are saying a exact 7788 and it's
> connected.....see for yourself...
>
> if i mistyped or got you thoughts wrong feel free to
> correct..
>
>
>
> using your string i obtain nothing
> route-server.east>sh ip bgp reg ^7788 [0-9]* [0-9]*$
> route-server.east>
>
> observ the string sh ip bgp reg ^7788_[1-9]*$
> ---that is with the
> underscore
> route-server.east>sh ip bgp reg ^7788 [0-9]* [0-9]*$
>
> route-server.east>sh ip bgp reg ^7788_[1-9]*$
> BGP table version is 97446699, local router ID is
> 216.191.65.118
> Status codes: s suppressed, d damped, h history, *
> valid, > best, i -
> internal
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric
> LocPrf Weight Path
> *>i64.26.128.0/18 216.191.224.1
> 100 0 7788 7788 i
> * i 216.191.224.1
> 100 0 7788 7788 i
> *>i192.203.106.0 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i192.222.1.0 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i192.222.2.0/23 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i192.222.4.0/22 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i192.222.8.0 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i198.96.127.0 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i198.96.199.0 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i199.71.68.0 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i204.138.103.0 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i204.187.103.0 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i204.225.145.0 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i205.207.175.0 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i205.233.68.0 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i206.51.251.0 216.191.224.1
> 100 0 7788 i
> * i 216.191.224.1
> 100 0 7788 i
> *>i206.191.0.0/18 216.191.224.1
> 100 0 7788 7788 i
> * i 216.191.224.1
> 100 0 7788 7788 i
> *>i209.217.64.0/18 216.191.224.1
> 100 0 7788 7788 i
> * i 216.191.224.1
> 100 0 7788 7788 i
> route-server.east>
>
> observe without the underscore sh ip bgp reg ^7788
> [1-9]*$
>
> route-server.east>sh ip bgp reg ^7788 [1-9]*$
> BGP table version is 97446794, local router ID is
> 216.191.65.118
> Status codes: s suppressed, d damped, h history, *
> valid, > best, i -
> internal
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric
> LocPrf Weight Path
> *>i64.26.128.0/18 216.191.224.1
> 100 0 7788 7788 i
> * i 216.191.224.1
> 100 0 7788 7788 i
> *>i206.191.0.0/18 216.191.224.1
> 100 0 7788 7788 i
> * i 216.191.224.1
> 100 0 7788 7788 i
> *>i209.217.64.0/18 216.191.224.1
> 100 0 7788 7788 i
> * i 216.191.224.1
> 100 0 7788 7788 i
> route-server.east>sh ip bgp reg ^7788_[1-9]*$
>
>
>
>
> Michael Snyder wrote:
>
> > _ (Matches a comma (,), left brace ({), right
> brace (}), the beginning
> > of the input string, the end of the input string,
> or a space.
> >
> > Steve I just wanted to match a space. Thats why I
> didn't use _ ,
> Cisco
> > shows examples of not using _ to match spaces. In
> other words, a
> space
> > char will match a space character.
>
=== message truncated ===
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