Re: bgp route-map

[Haesu <haesu () towardex com>]

Yes, I've tried that too.. But what I am thinking of doing is, using a route-map/bgp-announcement based version of 
building 'prefix-list' or 'distribute-list' to decide whether to accept route or not..

But as you said, I don't think that is possible heh..

Thanks!
-hc

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

On Mon, Aug 25, 2003 at 02:57:57PM -0400, ww () styx org wrote:
> I don't think what you are suggesting is directly possible, although I can think of 
> something that accomplishes the same thing, and only requires extra configuration on 
> the peering session with the route server. 
>  
> For prefixes recieved from the bogon route server, apply a route map that will (1) 
> send traffic to a Null0 bit sink and (2) set the local preference for these routes to a 
> value suitably large so that the same prefixes learned from other peers never get 
> used. 
>  
> -w 
>  
> On Mon, 25 Aug 2003 14:39:59 -0400, Haesu wrote 
> > 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 up.. 
> >  
> > 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. 
> >  
> > Thanks! 
> >  
> > -hc 
> >  
> > --  
> > Sincerely, 
> >   Haesu C. 
> >   TowardEX Technologies, Inc. 
> >   WWW: http://www.towardex.com 
> >   E-mail: haesu () towardex com 
> >   Cell: (978) 394-2867