Spam Filtering

As of February 15th, 2008 spam filtering is done in two steps. In the first step, the originating IP number of an e-mail message is checked against the SBL-XBL Spamhaus block list. If the IP shows up on this block list then the message is rejected and a 550 error code is returned to the originating server. About 2/3rds of spam are found via this first step. We've been using the SBL-XBL Spamhaus block list for many years and have yet to receive a complaint about a false positive (a rejected e-mail message that was not spam).

Nearly all remaining spam is detected in the second step by SpamAssassin. SpamAssassin spam filtering is turned on by default for all e-mail accounts. E-mail messages that score high enough to meet the SpamAssassin threshhold can be either flagged and stored in the e-mail box or automatically deleted at the server. Because of the very low level of false positives and the fact that e-mail addresses can be whitelisted, we recommend that messages that meet the SpamAssassin threshhold be automatically deleted at the server.

• Domain administrators can optionally configure spam filtering for all e-mail boxes in a domain.Note - the domain administrator can be EPCS or this function can be done by the domain owner.
• Individuals can optionally configure spam filtering for their individual e-mail box.

Spam filtering can be enabled or disabled for individual e-mail boxes. The spam threshold can be modifed for each individual e-mail box (although we recommend that the threshold be left at it's default value, 7). E-mail messages that exceed the spam threshold can be automatically deleted at the server (recommended) or flagged and placed in the e-mail box. E-mail addresses can be exempted from spam filtering by placing the address in the Whitelist for the e-mail box.

Individuals who may want to configure their own e-mail box parameters should contact their Domain Administrator. Domain Administrators who may want to configure their e-mail boxes should contact EPCS. EPCS will e-mail instructions to Domain Administrators.

Not all messages score high enough to be flagged as spam, but all messages are scored by SpamAssassin. To view the score for unflagged messages

1. Open the message in Microsoft Outlook or Outlook Express
2. Click File / Properties / Details

The score is labled "score" in a header line that looks something like
X-Spam-Status: No, score=2.4 required=7.0 tests=AWL,BAYES_00,HTML_MESSAGE autolearn=ham version=3.0.5

In the above example the spam score is 2.4 and the threshold for flagging the message as spam is 7.0.