Q): How do you know which messages are spam?
A): Our junk mail filter is a system that we have developed in house. We filter spam in a three-step process.
First we use what we call "bait" e-mail addresses. We have hundreds of e-mail addresses that we use to actively look for spam. We take those spam messages and run them through a process that we've created where we create a fingerprint for each message. Those fingerprints are added to our database.
Secondly, when new e-mail enters our network, we fingerprint each message and cross reference our database to see if there is a match. If there is a match, the message is marked as spam.
If there is no match, we then run the message through a series of test in which we look at different aspects of the message including the header, subject, and content of the message. These tests give the message a score and if that score hits a certain threshold, we mark that message as spam.
This whole process takes less than a second to perform.
Q): What happens to the spam?
A): As the administrator, you have four options in regards to the junk.
The first, and most popular, option is to leave the junk e-mail on our network. As we catch the junk e-mail, we create a temporary junk e-mail box for each of your users. We then notify each user that they have junk e-mail on our server and we give them a link to a web-based control panel where they can check it. As the administrator, you can set the notification interval. We hold the junk e-mail on our network for 30 days before it is deleted.
The second option is to redirect all the junk mail to a single e-mail address. For example, spam@yourcompany.com.
The third option is to have us insert an x-header. The junk e-mail is delivered to your mail server giving you the ability to reroute the e-mail via the x-header variable.
The fourth option is the ability to modify the subject. For example, you could insert the word JUNK before the subject so that the individual users could set up their own filters at the e-mail client level. | 
