Enabling Port 465 on a Postfix Mail Server

Configuring a mail server can become more challenging due to the default port used for mail delivery (port 25), which is increasingly blocked by internet service providers. To overcome this issue and enable both sending and receiving emails using IMAP/POP/SMTP, you can activate port 465 (smtps) in Postfix.

To do this, edit the file « /etc/postfix/master.cf » 

Remove the # at the beginning of the following line:

#smtps     inet  n       -       -       -       -       smtpd

Save the file, then restart Postfix using the following command:

/etc/init.d/postfix restart

You should now be able to send emails via SMTP using port 465.