Here are a few links to sites that we hope you'll find useful and informative. We can't guarantee or fully endorse the information on these sites, but we've found many of them valuable.

Spam Prevention Early Warning System (SPEWS): http://www.spews.org/

Enter an IP number and see if the operators of this site have received spam from it. The depth and breadth of information here is amazing... and not just a little frightening. If there's a major spamming operation in existence, it's listed here, along with upstream providers, partners in crime, and more. An excellent resource for anyone trying to connect the spam dots.

The MAPS(SM) Non-confirming Mailing List (NML): http://mail-abuse.org/nml

The site says it's "a database of Internet Protocol addresses (IP addresses) which have been demonstrated to be the sources of mailing lists which do not fully verify the email addresses on their list. This means that they do not confirm that the owner of the email address that is placed on their mailing list has, in fact, granted their permission to be included on the mailing list." ...Excellent! This brand-new database could be a very valuable resource as opt-out spam continues to become a larger threat.

Don Doumakes' site on his experiences with spam sent via PacBell: http://pinkbell.net

From the site: "Pacific Bell Internet is friendly to spammers... I've been receiving spam since November 2000 from cc-inc.com, a customer of pbi.net. Unlike reputable Internet service providers, pbi.net tolerates this violation of their own Acceptable Use Policy, as evidenced by their letting it go on for months. Since the spammer is based in Torrance, California, and does not mark the spam with 'ADV' in the header, this is also a clear violation of the California Business and Professions Code, Section 17538.4. If you're doing business with pbi.net, or planning to do so in the future, I strongly suggest that you take your business elsewhere. Don't take my word for it, look at the evidence...."

Need guidance for running a spam-free mailing list? Take a look at these pages...

http://spam.abuse.net/marketerhelp/
http://mail-abuse.org/manage.html

Looking for a blocking list? Here are a few lists, plus links to extensive lists of other blocklists:

ex.dnsbl — Domain-based blocklist compiled and used by DNS providers. Can be used by DNS service providers and web hosts who want to vet a client before signing a contract:
http://www.dnsbl.org/ex.dnsbl.php3

SPEWS' list of links to block lists:
http://www.spews.org/lists.html

Tired of Verio and its inability/unwillingness to terminate spammers? Try this:
http://www.the-foxhole.org/verio.txt

Spamware vendor / supporter lists:
http://www.sengir.demon.co.uk/spam_sites.html

Misc. Links for Administrators

Anti-Spam Provisions in Sendmail 8.8 — Information on how to block spammers:
http://www.sendmail.org/antispam.html