Advanced Dynamic Ramblings

Spam email can be a very inconvenient problem, especially for those that host their own mail server. The spam messages were coming in to our server at about 100 per day per user when we decided to implement a real solution.

After some research, we decided to implement Postini filtering. Postini’s filter works on the messages BEFORE they ever hit your mail server. This reduces bogus traffic to your mail server, and also protects it from bad things like Directory Harvest attacks. Directory Harvest attacks are an attempt to retrieve a list of all the valid email addresses at a domain.

The setup process can seem a bit daunting, but proves to be relatively easy and transparent. One big concern of mine was about making changes to the MX records in DNS. I’m quite familiar with this process, but I found it difficult to determine what would happen when mail was directed to Postini. Specifically, I was concerned that if I made the MX change before I created the users in Postini, messages would start bouncing.

It turns out that when users are created in Postini, it simply activates the filtering for that email address. Messages to email addresses not loaded into Postini simply pass through unaffected. Very nice.

Since Google has acquired Postini, you can get the service for a very affordable $3 per user per year.

Check it out here: http://www.google.com/a/help/intl/en/security/compare.html