From: trust.hogo@sarcom.com
Date: Wed Feb 19 2003 - 10:52:50 GMT-3
To add on to what Peter just said. Remember your true AS to EBGP neighbors
is 4799 not 65013. So in other words the question is asking you to tag all
routes passing thru your AS to AS111 with the no-export community. In this
case you do not need the AS-Path ACL.
-----Original Message-----
From: Peter [mailto:peter@cyscoexpert.com]
Sent: Tuesday, February 18, 2003 10:31 PM
To: ccielab@groupstudy.com
Subject: Re: BGP & community
The route-map is applied before the AS gets prepended, so your as-path ACL
should have ^$ if you want to tag all AS 4799 internal routes with the
no-export community or if you need to tag everything then you would not need
to use any as-path ACL, just tag everything in a single route-map sequence.
_____________________________
Peter
#7247 (R&S, Security)
CyscoExpert Corp.
4433 W. Touhy Ave. Suite 410
Lincolnwood, IL 60712
Phone (847) 674-3392
Toll Free (866) CyscoXP (297-2697)
Fax (847) 674-2625
----- Original Message -----
From: "pita40" <pita40@hotmail.com>
To: <ccielab@groupstudy.com>
Sent: Tuesday, February 18, 2003 6:30 PM
Subject: BGP & community
> I have a question from one of the commecial labs.
>
> Configure BGP such that BGP routes learned by AS 111 from AS 4799 are
> not passed onto their EBGP peers
>
> I used the first config with as-path. When I go to the bgp peer (BB1)
> to
look
> at the attribute for the routes it learned from R1 I get a shock that
> it
is
> not advertising to any peer.
> When I remove as-path statement I get not advertised to EBGP peer
> which is
the
> correct answer.
> Please help clarify why the routes are behaving like this.
>
> R1
>
> router bgp 65013
> bgp confederation identifier 4799
> bgp confederation peers 65053
> neighbor 150.50.33.33 remote-as 65013
> neighbor 150.50.33.33 update-source Loopback0
> neighbor 150.50.111.111 remote-as 111
> neighbor 150.50.111.111 send-community
> neighbor 150.50.111.111 route-map comm out
> no auto-summary
>
>
> ip as-path access-list 11 permit _4799_
>
>
> route-map comm permit 10
> match as-path 11
> set community no-export
> !
> route-map comm permit 20
>
> With the above config I get the following on BB1 with is nei
150.50.111.111
>
> bb1#sh ip bgp 133.133.133.0 255.255.255.0
> BGP routing table entry for 133.133.133.0/24, version 47
> Paths: (1 available, best #1)
> Not advertised to any peer
> 4799
> 150.50.111.1 from 150.50.111.1 (200.200.11.11)
> Origin incomplete, localpref 100, valid, external, best, ref 2
>
> When I remove the as-path command like this
>
> route-map comm permit 10
> set community no-export
>
> I get this on BB1
>
> bb1#sh ip bgp 133.133.133.0 255.255.255.0
> BGP routing table entry for 133.133.133.0/24, version 76
> Paths: (1 available, best #1, not advertised to EBGP peer)
> Not advertised to any peer
> 4799
> 150.50.111.1 from 150.50.111.1 (200.200.11.11)
> Origin incomplete, localpref 100, valid, external, best, ref 2
> Community: no-export
This archive was generated by hypermail 2.1.4 : Sat Mar 01 2003 - 11:06:29 GMT-3