[CentOS] Re: Problem with some SMTP MTAs

On Feb 20, 2007, at 11:46 AM, Edward Milstein wrote:

> Do you mind sharing how you implemented the drop list as a  
> access.db filter??  How did you represent the various network blocks??


Here's how I do it.  This used to be in the completewhois.com tools  
section, but I can't find it anymore.

Requires Sendmail's cidrexpand.  Apologies for the FreeBSD  
references....

#!/usr/bin/perl
#
# This script is used to convert list of ip blocks in cidr format into
# script that can be run to setup linux firewall to filter those blocks
# Script is written by William Leibzon for Completewhois Bogons Project:
# http://www.completewhois.com/bogons/
#
# $1 - should be list of ip blocks in cidr format
#
# Hacked up to format the drop list for feeding to sendmail's cidrexpand
# script to provide a list of net ranges to feed to sendmail's access  
table.
# The cidrexpand script is available in the contrib directory of your
# sendmail distribution. (/usr/src/contrib/sendmail/contrib/cidrexpand
# on FreeBSD.)
#
# Thanks to William Leibzon for the original script and Eric Kagan and
# Steve Glines for the inspiration.
# --Chris Boyd cboyd (at) gizmopartners 1-2-05
#
# Recommended usage:
# droptosend <droplist> | cidrexpand | sort | uniq
# (cidrexpand has some odd bugs that cause it to make duplicate lines)

$cidr_filename=@ARGV[0];

if ($cidr_filename eq "") {
   print "Usage: droptosend cidr_list_file\n";
   exit;
}
open ($cidr_fh, $cidr_filename)
   or die "can't open file $cidr_filename: $!";

while (<$cidr_fh>) {
   $line=$_;
   ($ip1,$ip2,$ip3,$ip4,$mask) = /^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\. 
(\d{1,3})\/(\d{1,2})/;
   if ($ip1 ne "" && $ip2 ne "" && $ip3 ne "" && $ip4 ne "" && $mask  
ne "") {
     print "$ip1.$ip2.$ip3.$ip4/$mask        ERROR:5.7.1:550 see  
http://www.spamhaus.org/drop/\n";
   }
}