Mail transport protection
SMTP server-level filtering is secured by a specialized plugin which provides protection in the form of antivirus, antispam and user-defined rules.
When a message arrives through the SMTP, the following actions are taken in the scanning sequence:
1. The message is scanned using the Greylisting technique (if enabled). For more information, see the chapter antispam protection.
2. The message is then scanned by the user-defined rules. See the chapter rules for more information on how they work.
3. The message is scanned by the antispam module.
4. The message is scanned by the antivirus module.
If the message is infected or recognized as a spam, the appropriate action is taken. If the message is clean, it will be delivered to the recipient.