We are still working to tune a newly installed spam solution. This affects all servers EXCEPT the Exchange servers. Spam is a very hard thing to deal with these days. In the late 1990’s and early into this century it was fairly easy. Rules published the included common keywords or phrases, known IP addresses of spammers, etc.

Today, [good] spammers are very smart. They have figured out all kinds of ways to throw up the standard filtering. Most of these tactics involve changing their IP address, relaying mail through other servers, and many other loopholes they have found over the years.

Our new spam solution does the standard checks that will block 80% of all spam. However, the other 20% is the hardest. As of today (9/28/2009), our spam filter has over 95 different checks to determine if messages are legit. Nobody can guarantee 100% spam detection, but when we are done tweaking, we should be in the upper 90’s.

One factor our system uses is by learning from outbound messages. This isn’t a new technique, but helps reduce bounces or spam detection of users you frequently send messages to. This takes at least 1-2 days and we suggest a week before it really starts to work.

Please check our knowledgebase to find articles and HOWTOs pertaining to spam filter. We have posted articles on how to report spam that was missed, whitelist addresses/entire domains, and moving legit messages to your inbox.