Configuring mail settings : Configuring the built-in MTA and mail server : Configuring the host name, port numbers, relay, mail queue and DSN : Configuring relay server options
 
Configuring relay server options
Configure an SMTP relay, if needed, to which the FortiMail unit will relay outgoing email. This is typically provided by your Internet service provider (ISP), but could be a mail relay on your internal network.
If the SMTP relay’s domain name resolves to more than one IP address, for each SMTP session, the FortiMail unit will randomly select one of the IP addresses from the result of the DNS query, effectively load balancing between the SMTP relays.
If you do not configure a relay, for outgoing email delivered by the built-in MTA, the FortiMail unit will instead query the DNS server for the MX record of the mail domain in the recipient’s email address (RCPT TO:), and relay the email directly to that mail gateway. For details, see “When FortiMail uses the proxies instead of the built-in MTA” on page 260.
 
Server relay is ignored if the FortiMail unit is operating in transparent mode, and “Relaying using FortiMail’s built-in MTA versus unprotected SMTP servers” on page 266 is enabled.
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Server relay is ignored for email that matches an antispam or content profile where you have enabled Deliver to alternate host.
 
GUI item
Description
Relay server name
Enter the domain name of an SMTP relay.
 
Relay server port
Enter the TCP port number on which the SMTP relay listens.
This is typically provided by your Internet service provider (ISP).
Use SMTPs
Enable to initiate SSL- and TLS-secured connections to the SMTP relay if it supports SSL/TLS.
When disabled, SMTP connections from the FortiMail unit’s built-in MTA or proxy to the relay will occur as clear text, unencrypted.
This option must be enabled to initiate SMTPS connections.
Authentication Required
If the relay server requires use of the SMTP AUTH command, enable this option, click the arrow to expand the section and configure:
User name: Enter the name of the FortiMail unit’s account on the SMTP relay.
Password: Enter the password for the FortiMail unit’s user name.
Authentication type: Available SMTP authentication types include:
• AUTO (automatically detect and use the most secure SMTP authentication type supported by the relay server)
• PLAIN (provides an unencrypted, scrambled password)
• LOGIN (provides an unencrypted, scrambled password)
• DIGEST-MD5 (provides an encrypted hash of the password)
• CRAM-MD5 (provides an encrypted hash of the password, with hash replay prevention, combined with a challenge and response mechanism)