I configured Postfix, after a time I discovered I am blocked from sending emails because my network is on a blacklist (it's a dynamic IP). So, sometimes Outlook does not connect to send (still gets the mails). Then I changed the SMTP on the master file and I set port 587 on this way:
587 inet n - - - - smtpd
The problem is now I can't receive, I get these errors:
The recipient server did not accept our requests to connect
On my domain manager I set the A register to point to his own IP, and the MX to point to my domain name (the MX is mydomain.com, not mail.mydomain.com, but all was configured this way with Postfix).
I don't understand what could be wrong, any idea of this issue?
Best Answer
To receive emails from other servers, you need to be listening on port 25. Port 587 is the submission port, intended for clients to submit mail for delivery. Other mail servers will never try to connect to this port.