I tested IPs from your list here: http://www.dnsbl.info/dnsbl-database-check.php e.g. 59.152.101.78 is listed, only 3 times but still, 117.199.133.23 is listed several times. Whereas my current dynamic IP is listed at b.barracudacentral.org which may be a bit harsh. ;-) You may take a look at DNSBL ( http://en.wikipedia.org/wiki/DNSBL ). I do not know how to automate this. ;-)