How to classify mail by numeric IP address of sender or relay?

[Mikael Hakman]

How to classify (as spam or ham) mail sent from or relayed by a specified 
numeric IP address of a host or a subnet? Example:

Received: from finklfan.com (unknown [222.111.110.107])
by rushmore.scorpionshops.com (Postfix) with SMTP id 1D8207355A
for <[EMAIL PROTECTED]>; Sat,  5 Mar 2005 16:11:57 +0100 (CET)
Received: from wamu.com (mtav004.erms-02.wamu.com [167.88.201.35])
by finklfan.com (Postfix) with ESMTP id 13F3E5F8C6
All mail from or relayed by hosts on 167.88.0.0/255.255.0.0 network should 
be classified (as ham or spam depending on the needs). Also, independently 
from previous, all mail from or relayed by hosts on 
222.111.110.0/255.255.255.0 network should also be classified.

Thanks/Mikael