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The "Message Tests" Page
Use this page to maintain a set of rules that should be applied to mail messages that are not covered by either a whitelist or blacklist. The rules allow you to perform comprehensive tests on the actual content of the message, and can be linked together to create chains of tests. Each rule can have a weight, and after all the rules have been applied, Mercury adds up the combined weights of all the rules that matched the message: if the combined weight is greater than a value you specify, the message is marked as unacceptable.
Content processing rules file
Enter in this field the name of a file containing rules written using the Pegasus Mail/Mercury content control filtering language - Mercury will apply these rules to any message that is not trapped by either the black or white lists. You can either edit the rule file by clicking the Edit button next to the field, or by using an external text editor. The internal editor has a filesize limitation of 32KB - if your ruleset file is larger than this, you will need to use an external editor to edit it.
Checking syntax
When you are editing your rule file, you can check that the rules you have entered are syntactically correct by clicking the Check Syntax button in the rule editor: if Mercury encounters any errors in the rule set, it will pop up a dialog describing the error and place the cursor on the line where the error occurred.
Weight at or above which this definition activates
Within the rule file, each rule can be assigned a weight, which is a numeric value; after all rules have been processed, Mercury adds together the weights assigned to every rule that matched the message - if the total weight is greater than or equal to the value you enter here, the message will be deemed "unacceptable" and will be subject to the action you define on the "Actions" page of the editor.
Check at most this many bytes in each message
If you enter a value greater than zero here, Mercury will only scan that many characters in each message when applying your content control rule set. This can reduce the time taken to perform content control, but can also result in less undesirable mail being detected. If you find that Content Control is taking a significant amount of time on your system (for instance, if you receive many large messages), entering a value of around 8000 in here will typically provide a good balance between speed and detection.
Note that when scanning multipart messages, Mercury adds together the size of each text section it scans to calculate the number of bytes it has scanned - it does not simply blindly read through the file.
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