Circa 3000 employs sophisticated detection technology to monitor your e-mail messages for spam (unsolicited advertisements). Messages are branded with a hidden "spam weight" value, indicating the message's likelihood of being an unwanted advertisement. Circa 3000 takes no other action on your mail. You must setup filters in your mail client software to act on those hidden values.
Spam Weight
A message's spam weight is determined by the number and severity of spam-detection tests failed by the message and is recorded in the message's headers. [View a message's headers by selecting "view source" (or similar) in your mail client.] The header 'X-Spam-Weight' contains the message's overall spam weight.
More importantly, the header 'X-Spam-Tests-Failed' contains, as it's name suggests, a list of spam tests failed by the message. These include weight-range tests that categorize the message into one of six general weight ranges. The 'X-Spam-Tests-Failed' header typically looks like this:
X-Spam-Tests-Failed: IPNOTINMX, SPAMHEADERS, SPAMCOP, BLACKLIST01, WEIGHT05, WEIGHT10, WEIGHT15, WEIGHT20
The six possible weight ranges (weight tests) are shown below. A message with overall spam weight of five or greater will fail the WEIGHT05 test. Likewise a message with overall weight of fifteen or greater will fail the WEIGHT05, WEIGHT10 and WEIGHT15 tests.
- WEIGHT30 (probably spam)
- WEIGHT25
- WEIGHT20
- WEIGHT15
- WEIGHT10
- WEIGHT05 (probably not spam)
Creating Mail Filters
In order to quarantine or discard messages of a particular weight range, you will need to setup filters in your mail client. Because each mail client is different, we cannot provide specific examples here. However, we recommend that you follow these sample filters to start:
- Header 'X-Spam-Tests-Failed' contains WEIGHT25 - Move to Trash folder
- Header 'X-Spam-Tests-Failed' contains WEIGHT10 - Move to Quarantine subfolder
These filters will discard all e-mail with a weight of 25 or higher; quarantine all messages with a weight of 10 to 24; and leave all other mail alone.
These filters assume that a Quarantine subfolder is available and that a Trash folder is provided by your mail client which contains deleted messages. Also, be certain to follow the prescribed filter order because a message with WEIGHT20, for example, will also contain all weights below it: WEIGHT15, WEIGHT10 and WEIGHT05. Test for the highest weights first, so that the desired action is taken.
As you become comfortable with the accuracy of lesser weights, you will want to modify those filters to take more aggressive action. For example, you may opt to discard all mail of WEIGHT15 or higher.
Use At Your Own Risk
Spam detection is not 100% accurate and may produce false positives, whereby legitimate mail is misidentified to contain unsolicited advertisements. It is for this reason that Circa 3000 provides only spam DETECTION (without ACTION) and does not provide or imply warranties of any kind. How you use this information is entirely your responsibility. If you cannot afford to lose any legitimate mail to misdetection, then we strongly recommend against taking action of any kind based upon the anti-spam information we provide to you. |
