FortiMail
FortiMail provides advanced, multi-layer protection against the full spectrum of email-borne threats
gmichailidis
Staff
Staff
Description This article describes how to prioritize IPv6 for outgoing emails.
Scope All FortiMail versions.
Solution

To use IPv6 addresses when relaying outgoing emails.

 

When FortiMail delivers email to a host name, it does DNS AAAA and A record lookup.

 

Use the commands below to:

 

- ipv6: try IPv6 only. This setting is not recommended.

 

gmichailidis_0-1659617542735.png

 

- ipv6-ipv4: try IPv6 first, then IPv4.

 

However, if the AAAA record does not exist, the extra AAAA DNS lookup for IPv6 addresses will potentially cause email delivery delay.

 

gmichailidis_1-1659617568076.png

 

# config system mailserver

    set smtp-delivery-addr-pref {ipv6-ipv4 | ipv6}

end