Note: Note:
|
Control of the configurable rule filter is only possible
if you have selected to use the ADVANCED
setting on this
page. Setting
to use the BASIC pre-configured rule filter will not allow you to see
the Rule node in the left pane of the Praetor administration MMC. |
As you know, Praetor filters mostly at the message level with the DNS blacklist check also available to function at the SMTP protocol level. There are other protocol level filtering but this occurs via the IIS Services Manager:
IP addresses
Domain names
Sender addresses
The message level filtering, however, is entirely based upon the Bayesian statistical technique and filtering rules using heuristics about the message and other conditions that you control. These rules provide substantial flexibility and power via a convenient user interface that is similar to the rules wizard found in Microsoft Outlook.
This chapter provides a discussion on message level filtering rules, the types, conditions and their lists, actions, exceptions, and templates. Equally important is a discussion on rule ordering, a topic that has significant bearing to Praetor's efficient operation. Improper ordering can result in Praetor spending more time than is necessary to determine if a message is spam. Some general ordering guidelines will be presented so that you can adjust Praetor to perform optimally for your site.
Praetor stores the rules and their order into a single script file. This rule script file is used for each message that Praetor processes. The scripting is expressed as a Microsoft Visual Basic Script and you can learn more by clicking here.
Regardless of the rule type, global or conditional, the direction of the message being analyzed is an important determination of what rules will be tested. Praetor determines the direction of the message by checking the email address(es) of each intended recipient. If every address is found with a domain that was configured as a local domain in Praetor, then the message is considered as inbound. Otherwise the message is considered as outbound to the Internet.
Praetor will treat the message as a whole and perform its filtering consistently across all the recipients it finds. It does not split recipients and uses the inbound rules on one set of recipients, and the outbound rules on another set. Thus if a message contains mixed recipients with some being in the local domain(s) and at least one is out of the local domain(s), the message is considered as being outbound.