[c-nsp] Prefix-list help

Paul Stewart paul at paulstewart.org
Tue Oct 16 08:49:05 EDT 2007

We've been running Team Cymru's bogon filtering for a long time via eBGP
sessions .... we use it to filter out bogons all the time and never had an

It doesn't answer your question but might be worth looking at.. good guys to
deal with in my opinion...;)



-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Chris O'Hair
Sent: Tuesday, October 16, 2007 7:53 AM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] Prefix-list help


This morning, while checking for an internal route to, I noticed
a rather large supernet was advertised from one of our upstream ISPs:

#sh ip bgp
BGP routing table entry for, version 3286876

I have a prefix-list for incoming updates to filter out bogons but its not
checking for minimum lengths.  Can someone help me out with a prefix-list
statement that will block this nastiness but not remove any useful

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