nanog mailing list archives

Re: Repeated Blacklisting / IP reputation


From: Jon Lewis <jlewis () lewis org>
Date: Tue, 8 Sep 2009 15:08:38 -0400 (EDT)

On Tue, 8 Sep 2009, Wayne E. Bouchard wrote:

This is not actually a new problem. ISPs have been fighting this for
some time. When a dud customer spams from a given IP range and gets it
placed in various RBLs, when that customer is booted or otherwise
removed, that block will probably get reissued. The new customer then
calls up and says, "my email isn't getting through." All it takes is a

The difference/issue here is that it's easy for you when turning down or turning up a customer to check the IP space being revoked/assigned in the various popular public DNSBLs, sparing your customers the headache of being assigned blacklisted IPs. Until your next customer starts using the space and can't send us email, you have no way of knowing that we null routed the subnet on our MX cluster.

----------------------------------------------------------------------
 Jon Lewis                   |  I route
 Senior Network Engineer     |  therefore you are
 Atlantic Net                |
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