FortiMail operation modes

FortiMail units can run in one of three operation modes: gateway mode, transparent mode, and server mode.

Gateway mode

• The FortiMail unit acts as a mail transfer agent (MTA), or email gateway, relaying email to and from the email servers that it protects.
• Simple DNS MX record change redirects email to FortiMail for antispam and antivirus scanning.
• FortiMail does not locally store email unless queued or quarantined.

Transparent mode

• The FortiMail unit transparently proxies or relays email traffic to and from the email servers that it protects.
• Eliminates the need to change existing mail server network configuration.
• FortiMail does not locally store email unless queued or quarantined.

Server mode

• The FortiMail unit operates as a standalone, full-featured email server and MTA.
• The FortiMail unit locally stores email for delivery to its email users. Email users can access their email using FortiMail webmail, POP3, or IMAP.

All operation modes can scan email traffic for viruses and spam, and can quarantine suspicious email and attachments.