User Guide

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AsyncOS 9.1.2 for Cisco Email Security Appliances User Guide
Chapter 9 Using Message Filters to Enforce Email Policies
Message Filter Rules
Description and Examples of Message Filter Rules
The following section describes the various message filter rules in use and their examples.
Related Topics
• True Rule, page 9-23
• Valid Rule, page 9-23
• Subject Rule, page 9-23
• Envelope Recipient Rule, page 9-24
• Envelope Recipient in Group Rule, page 9-25
• Envelope Sender Rule, page 9-25
• Envelope Sender in Group Rule, page 9-25
• Sender Group Rule, page 9-26
• Body Size Rule, page 9-26
• Remote IP Rule, page 9-27
• Receiving Listener Rule, page 9-27
• Receiving IP Interface Rule, page 9-28
• Date Rule, page 9-28
• Header Rule, page 9-28
• Random Rule, page 9-29
• Recipient Count Rule, page 9-30
• Address Count Rule, page 9-30
• Body Scanning Rule, page 9-31
• Body Scanning, page 9-31
• Encryption Detection Rule, page 9-32
• Attachment Type Rule, page 9-32
• Attachment Filename Rule, page 9-33
• DNS List Rule, page 9-34
• SenderBase Reputation Rule, page 9-34
• Dictionary Rules, page 9-35
• SPF-Status Rule, page 9-37
• SPF-Passed Rule, page 9-39
• S/MIME Gateway Message Rule, page 9-39
• S/MIME Gateway Verified Rule, page 9-40
• Workqueue-count Rule, page 9-40
• SMTP Authenticated User Match Rule, page 9-40
• Signed Rule, page 9-42
• Signed Certificate Rule, page 9-43