You can create rules that filter email messages according to the conditions you specify or according to the email addresses of the sender or recipient. Conditions you can specify in the rule include: which header fields to scan, whether or not to search the body of an email message, and what keywords to search for.
You can create rules that can:
Filter messages that match any condition defined: This type of rule is capable of filtering content from any message during a scan. For details, see Adding a Content Filtering Rule for Any Matching Condition.
Filter messages that match all conditions defined: This type of rule is capable of filtering content from any message during a scan. For details, see Adding a Content Filtering Rule for All Matching Conditions.
This rule type is not available for Manual and Scheduled Content Filtering Scans.
Monitor the message content of particular email accounts: This type of rule monitors the message content of particular email accounts. Monitoring rules are similar to general content filter rules, except that they only filter content from specified email accounts. For details, see Adding a Content Filtering Monitoring Rule.
Create exceptions for particular email accounts: This type of rule creates an exception for particular email accounts. When you exempt a particular email account, this account will not be filtered for content rule violations. For details, see Creating Exceptions to Content Filtering Rules.
After you have created your rule, the Messaging Security Agent begins to filter all incoming and outgoing messages according to your rule. When a content violation occurs, the Messaging Security Agent takes action against the violating email message. The action that the Security Server takes also depends on the actions that you set in your rule.