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bgp route-map
From: Haesu <haesu () towardex com>
Date: Mon, 25 Aug 2003 14:39:59 -0400

Hi all,

Wondering if anyone would know whether such feature in IOS exists or not...

Most of the time, people use route-maps on bgp neighbors or peer-groups to set
an attribute,etc on a prefix that is being announced OUTbound or INbound.

However: On prefixes being announced to me INBOUND, is there a feature  to set
in route-map so that it checks whether the advertised prefix is already existing
in local RIB?

Like for example, I am one of the users who receive bogon advertisements from
Rob's route-server.

Now, when I receive prefixes either from my upstream AS or my customers doing
bgp with me, I can setup a route-map on the neighbor so that it compares the
prefix being announced by neighborAS with existing Rob's bogon prefix in the RIB
with bogon route-server community 65333:888.

If the prefix being announced gets a match with existing prefix with 65333:888
already in the router, the route-map would cause a DENY. Thus, making Rob's
bogon announcement from his route-server, a bogon route filtering list for me
to use on my customers/peers.. 

If you are not understanding what I am saying, feel free to yell at me to clear

This would make it much easier to create dynamic bgp-based route filtering list
in my opinion... I am not here to discuss the feasibility of whether doing or
inventing this dynamic method of filtering bgp routes; I am rather asking this
question to see if anyone is doing something similar to this as it may be useful.


  Haesu C.
  TowardEX Technologies, Inc.
  WWW: http://www.towardex.com
  E-mail: haesu () towardex com
  Cell: (978) 394-2867

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