From: Tim Lewin (tlewin@xxxxxxxxxxxxxxxxxxx)
Date: Wed May 02 2001 - 00:00:49 GMT-3
Darek
Your are correct. Thanks for the update.
Regards...Tim
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Darek Kuzma
Sent: Wednesday, 2 May 2001 12:55 AM
To: Tim Lewin
Cc: ccielab@groupstudy.com
Subject: Re: BGP route-filtering problem
Tim,
Both methods you provided may work however the configuration you provided
for 1)
in incorrect!
The syntax of the distance command is diffrent!
Here is how it should be configured:
router bgp 1
network 10.1.2.0 mask 255.255.255.0
network 10.1.6.0 mask 255.255.255.0
network 10.1.9.0 mask 255.255.255.0
network 10.1.12.0 mask 255.255.255.0
aggregate-address 10.1.0.0 255.255.0.0 summary-only
distance 255 0.0.0.0 0.0.0.0 11
!
access-list 11 permit 10.1.0.0 0.0.255.255
access-list 11 deny any log
in command distance 255 0.0.0.0 0.0.0.0 11
255 sets distance to 255 (= do not put in routing table)
FOR routes learned FROM 0.0.0.0 0.0.0.0 (local router)
FOR routes matching access list 11
0.0.0.0 0.0.0.0 may need additional explenation:
IP address which follows new AD is address of router advertising route
specified
in access list 11 NOT a network to adjust AD! 0.0.0.0 means that we will
adjust
AD for routes reciveied from or rather in this case originated by local
router
MISMETR01A#sh ip bgp 10.1.0.0
BGP routing table entry for 10.1.0.0/16, version 3
Paths: (1 available, best #1, table Default-IP-Routing-Table)
Not advertised to any peer
Local, (aggregated by 1 12.125.143.218)
0.0.0.0 from 0.0.0.0 (12.125.143.218)
Origin IGP, localpref 100, weight 32768, valid, aggregated, local,
atomic-
aggregate, best
MASK argument is also of special intrest:
(config-router)#distance 255 0.0.0.0. ?
A.B.C.D IP address mask
Online help description is misleading.
Mask 0.0.0.0 means EXACT MATCH because a bit set to 1 in the mask argument
instructs the router to
ignore the corresponding bit in the address value !!! So it work more like
wildcard mask.
If you want to adjust AD of all networks received/learned from routers with
IP
falling into range 10.1.0.0-10.1.255.255 you would configure:
distance 255 10.1.0.0 0.0.255.255 [optional access-list-number]
Thanks,
Darek
Tim Lewin wrote:
> Dan
>
> There are two ways you can stop the summary route to null appearing in
your
> route table.
> 1. Stop route being added to route table by forcing its admin distance to
> 255
>
> Router BGP 1
> Distance 255 170.0.0.0 0.255.255.255 (assuming 170.0.0.0 is your
summary
> route)
>
> 2. Use Distribute-list in under the BGP route process to stop the route
> being added to the route table.
>
> Router BGP 1
> Distribute-list 80 in
>
> access-list 80 deny 170.0.0.0 0.255.255.255
> access-list 80 permit any.
>
> Hope this helps
>
> Regards...Tim
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> Dan Skiptunas
> Sent: Tuesday, 1 May 2001 11:15 AM
> To: ccielab@groupstudy.com
> Subject: BGP route-filtering problem
>
> I have configured a aggregate route in BGP that needs to be filtered from
> the local routing table ,this route is causing routing problems by sending
> routes to null 0. Is it possible to filter locally generated routes from
> the routing table ?
>
> Dan Skiptunas
> Network Engineer
> NEC-BNS
> Office :203-461-9200 ex.421
> Pager : 888.672.8636
> **Please read:http://www.groupstudy.com/list/posting.html
> **Please read:http://www.groupstudy.com/list/posting.html
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