Chapter 15 Security Profiles : Email filter : Email traffic types to inspect
  
Email traffic types to inspect
The FortiGate unit examines IMAP, POP3, and SMTP email traffic. If your FortiGate unit supports content inspection, it can also examine IMAPS, POP3S, and SMTPS traffic. The options that you will see in the profile window are IMAP, POP3 and SMTP.