From: Jim Devane (jim@powerpulse.cc)
Date: Thu Mar 03 2005 - 19:37:35 GMT-3
It is extremely effective for getting a network stmt to work.
That is, you pop in a network stmt but do not have a matching route in the
route table, and thus the network stmt never goes into the BGP table and no
advert.
Case in point... you are advertising a /20 in two different places A and B.
You would prefer traffic fro a particular /24 to come in through point A. so
you through a network stmt in. but you don't have a route internally for a
/24 ( maybe two customers split it into /25's )
Throw in the network stmt, nail a static route to null 0 ( with a high admin
distance ( but less that 255 )) and voila! You have an exact match in the
routing table and bingo... you have it in your BGP table and can advert out
from A to other peers.
The are other ways to do the same thing, but this is one way to accomplish
it. Note: this may not be Internet friendly etc. but it is done.
Jim
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
jacque vincent
Sent: Thursday, March 03, 2005 12:09 PM
To: ccielab@groupstudy.com
Subject: BGP and null0 interface
I start doing bgp practice labs and I do not understand the use of tha
NULL0 interface. It is the first time I am using the static routes with
NULL0 interface.
Can somebody explain me when do we need to use the static route directed to
NULL0 interface in BGP ?
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