Am I right in assuming that these tools will only work properly if you run your own mail domain? I.E., for the average home user, who gets his/her mail from a POP3 server or IMAP server on their ISP, can such tools still be used? My current tool is a procmail filter called Spam Bouncer. It's basically a very complex set of procmail rules that tags messages as ok, bulk, possible spam, and definitely spam. It uses a scoring system which you can customize to decide what levels to use to tag messages. You can have probable and definite spam go to different places, and you can also filter some viruses. It comes with a sample .procmailrc file which you can modify to suit your needs. You can (and should,) create two files containing your legitimate email addresses. One is for mailing lists, and the other is for personal email. Such messages are stored automatically, and undergo no further processing. It really cuts down on false positives. This filter is updated frequently, so it's a good idea to check the web site every once in awhile. It catches almost all my spam. There is a special email address you can send spam that it misses to, so the author can look at it and add rules to catch it in future releases. Lastly, there are optional features to send complaints to spammers, and offer senders who get blocked a password to get their email through. I never use these features, but I can see how they might be useful to some people. The web page for this filter is at http://www.spambouncer.org. It works quite well with my setup of fetchmail retrieving my email, and sendmail only allowing connections from localhost.
