We recently got a chance to try out the anti-spam e-mail tool that comes with Horde e-mail services (available on selected web site hosts) and found their default algorithm to be exceptional!
We get more than a megabyte of mail a day and most of it is spam. They want us to be longer, thicker, sexier, make more money from home (than ten people can make going out to work), go into partnership with the Crown Prince of Nigeria (who has a trillion dollars in a Swiss bank that only we can help transfer, if we’d just have over our bank routing number) and get invites to see naked college girls have fun with their web cam for free (if only we’d give them our credit card number to prove we are over 18).
It was getting to the point that real, important mail was getting lost in the shuffle, so we turned on Spam Assassin, which sounds like Jet Li movie title, then watched it liquidate (well, it segregated, we liquidated manually) almost all of our spam and only a few pieces of spam we requested (junk mail from M-G-M, BMG and a few other sources used to fill our entertainment columns)! All we had to do is extract some of the spam we wanted to read and the rest went at the push of an FTP button as we deleted the folder marked “spam” – bam!
Spam Assassin has some built in algorithms for parsing these files (and you can get a report showing you what it segregated and telling you about the content it found that made it want to hide these from site) and you can customize your own parsing files to look for key indicators in the mail you receive to make this tool even more effective.
Spammers, however, are finding ways and means to defeate these filters! For example, the following lines fooled Spam Assassin with ease: Re: PZLA, the findirectors longawaited Re: HBVFGW, the man gazed Re: XYQUNLDK, alexandrovich berlioz before Allowing these spam messages to pass in to our mail box. Also, by replacing the letter "o" with the number zero "0" you can trick the filtering system as well! Such as: No m0re spam! This message would by-pass the filtering system. We still find that Spam Assassin continues to filter out better than 75% of the unwanted mail. We are currently waiting for the FTC to start the "No Spam" list so that we can get on that list and see if the new U.S. Anti-Spam law will really work...
We found the basic settings good enough for our needs and now we can easily find submissions from our contributing editors, press releases we requested and other more important mail without having to wade through two dozen pages of web based junk a day like we were getting before activating Spam Assassin!