SMTP E-mail Notification Error
Currently I have a mail server on my DMZ network were I can receive and send mail with no issues using port 25. The setup looks to be straight forward but I may be missing something.
Any help would be much appreciated.
Thanks in advanced.
I guess that mail.mydomain.com resolves to the public IP of your pfSense, which is forwarded in to the DMZ.
That loop is likely the issue.
You could do "split DNS" - in DNS Forwarder add a domain override for mail.mydomain.com (and maybe also mydomain.com) that resolves directly to the private IP in the DMZ. Then pfSense will send its mail direct to the server in the DMZ.
Is 'mail.mydomain.com' the genuine name of your mail server? You could always try entering the IP address of your mail system instead of relying on DNS (System/Advanced/Notifications tab). The notification email address (recipient) could just remain as 'firstname.lastname@example.org' - or whatever the actual address really is. You also might want to check to be sure that your mail server is set to allow inbound messages from your firewall from a trusted domain - otherwise, the mail server might reject the message as spoofed.
I tried using the DNS forwarder and using the public address for mail.mydomain.com but unfortunately this did not resolve the error but when adding the private address (172.16.0.4) in the E-Mail server textbox for notification all worked fine.