Chris O'Donovan wrote:
> If they have fixed IPs you can add them to the "Local
> Networks" panel in the server manager.
This has security implications, as they'll also be able to access the server-manager and other restricted services.
> You might also consider configuring IMAP/POP3/SMTP over SSL.
> There is a contributed HOWTO on doing this.
This doesn't allow SMTP relaying, which is what he was wanting to do.
The file you need to modify (via templates) is /var/spool/smtpd/etc/smtpd_check_rules.