From: gladston@br.ibm.com
Date: Tue Apr 26 2005 - 14:29:54 GMT-3
Testing a bit more revealed that this works:
r4#sh ip bgp regexp ^\(65300\)$
Network Next Hop Metric LocPrf Weight Path
*> 33.33.33.0/24 172.16.34.3 0 100 0 (65300) i
Andy, I think I got,now, what you told me. Each time there is a "(" or ")"
it is necessary to use "\" before that kind of character. And the AS Path
really contains the "(" and ")". I though it was just on the result of
the command.
Thanks
----- Forwarded by Alaerte Gladston Vidali/Brazil/IBM on 26/04/2005 14:26
-----
Alaerte Gladston Vidali/Brazil/IBM
26/04/2005 14:16
To
"Edwards, Andrew M" <andrew.m.edwards@boeing.com>
cc
<ccielab@groupstudy.com>, "bi.s" <bi.s@gmx.net>, "CCIE6296"
<ccie6296@aces-star.com>
Subject
RE: BGP - Filtering AS confederation
Thanks for the feeback,
I tried (), but could not achive the result:
The requirement is to allow only local originated routes using
filter-list; if there was no confederation, I would use empty AS --> ^$
r4#sh ip bgp regexp (65300)
Network Next Hop Metric LocPrf Weight Path
*> 33.33.33.0/24 172.16.34.3 0 100 0 (65300) i
*> 44.44.44.0/24 0.0.0.0 0 32768 i
*> 158.200.200.0/24 172.16.36.6 0 100 0 (65300) 600
1600 2500 500 i
It is necessary to allow only AS 65300.
If I use ^(65300)$ it does not work:
r4#sb
Network Next Hop Metric LocPrf Weight Path
*> 33.33.33.0/24 172.16.34.3 0 100 0 (65300) i
*> 44.44.44.0/24 0.0.0.0 0 32768 i
*> 158.200.200.0/24 172.16.36.6 0 100 0 (65300) 600
1600 2500 500 i
r4#
r4#
r4#sh ip bgp regexp ^(65300)$
r4#
If I use ^$, just routes not received from the confederation are matched:
r4#sh ip bgp regexp ^$
Network Next Hop Metric LocPrf Weight Path
*> 44.44.44.0/24 0.0.0.0 0 32768 i
I need to tell IOS to look for routes that has just (65300) and no other
ASs on the AS PATH.
You told me about "\". How would the expression be?
I tried some variations (like a blind guy) without success:
r4#sh ip bgp regexp ^\(65300)
% unmatched ()
% Invalid regular expression
r4#
r4#sh ip bgp regexp \^(65300)
r4#sh ip bgp regexp \(^65300)
% unmatched ()
% Invalid regular expression
r4#
Cordially
------------------------------------------------------------------
Alaerte
"Edwards, Andrew M" <andrew.m.edwards@boeing.com>
26/04/2005 12:48
To
Alaerte Gladston Vidali/Brazil/IBM@IBMBR
cc
Subject
RE: BGP - Filtering AS confederation
You need to alter the regexp to include the ( character with the "\("
From CCO
To use these special characters as single-character patterns, remove the
special meaning by preceding each character with a backslash (\). The
following examples are single-character patterns matching a dollar sign,
an underscore, and a plus sign, respectively:
\$
\_
\+
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/
fdial_c/fnsprt13/dafaapre.htm#wp1020344
HTH
andy
-----Original Message-----
From: gladston@br.ibm.com [mailto:gladston@br.ibm.com]
Sent: Tuesday, April 26, 2005 8:28 AM
To: ccielab@groupstudy.com
Subject: BGP - Filtering AS confederation
How can I match just a confederation AS whith regular expression?
R3#sh ip bgp reg
Network Next Hop Metric LocPrf Weight Path
*> 65.2.1.0/24 142.20.6.1 0 100 0 (65202
65206) 254 i
*> 65.2.2.0/24 142.20.6.1 0 100 0 (65202
65206) 254 i
*> 65.2.3.0/24 142.20.6.1 0 100 0 (65202
65206) 254 i
*> 65.2.4.0/24 142.20.6.1 0 100 0 (65202
65206) 254 i
*> 65.2.5.0/24 142.20.6.1 0 100 0 (65202
65206) 254 i
*> 200.200.1.0 142.20.125.1 0 100 0 (65202) i
R3#
R3#sh ip bgp regexp 65202$
Rack2R3#sh ip bgp regexp ^65202
What I am trying to achieve is to send just routes with empty AS to
external neighbor 150.100.20.254, using filter-list.
Should be the only solution to specify the internal ASs? (ip as-path
access-list 60 permit 65202)
If I use ^$ the internal routes received from confederation peers are
not allowed:
R3#sibs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down
State/PfxRcd
142.20.23.2 4 65202 197 189 48 0 0 02:51:19
2
150.100.20.254 4 254 189 189 48 0 0 02:48:47
13
R3#sh ip bgp ne 150.100.20.254 ad
Network Next Hop Metric LocPrf Weight Path
*> 66.66.66.0/24 142.20.6.1 0 100 0 (65202
65206) i
*> 200.200.1.0 142.20.125.1 0 100 0 (65202) i
R3#conf t
R3(config)#ip as-path access-list 60 permit ^$ R3(config)#router bgp
65203 R3(config-router)#nei R3(config-router)#neighbor 150.100.20.254 fi
R3(config-router)#neighbor 150.100.20.254 filter-list 60 out
R3(config-router)#neighbor 150.100.20.254 filter-list 60 out
R3(config-router)#^Z
R3#clear ip bgp * so
R3#sh ip bgp ne 150.100.20.254 ad
R3#sh ip bgp ne 150.100.20.254 ad
This archive was generated by hypermail 2.1.4 : Tue May 03 2005 - 07:55:09 GMT-3