Is it time to abandon bogon prefix filters?

Mon Aug 18 00:57:25 UTC 2008

Tomas L. Byrnes wrote:
> Since there are ways to dynamically filter the bogons, using BGP or DNS,
> I don't really see the need to stop doing so. If you're managing your
> routing and firewall filters manually, you have bigger problems than the
> release of Bogon space. 

Can you share the Cisco configuration snippet you recommend to 
dynamically FILTER bogons using BGP or DNS?  Not just inserting 
null-routes for the bogon aggregates, but preventing the acceptance of 
more-specifics that transits/peers/customers have managed to sneak past 
someone's filters (or lack thereof), please.

(Without an offline configuration generator, I postulate that it can't 
be done.)

pt