Postfix by default uses ports 25, 465 and 587. In my configuration, I enabled TLS encryption using the option smtpd_use_tls=yes in postfix's main.cf. This makes all smtp communications encrypted as far as I understand.

Since postfix takes only 1 certificate and doesn't support SNI, I would like to use nginx as a proxy to have the encryption decided by nginx based on SNI and domain name, as a proxy, and not by postfix.

I'm confused about the changes I have to do in postfix, and I would appreciate your help. Here are my questions:

1) When I send e-mails through my server, I use port 25. But what about receiving mail? Should I change all these ports that postfix uses (to replace them by nginx)? or just port 25 is enough?

2) When I use nginx as proxy, should I disable encryption in postfix? If I understand this whole thing correctly, then the internal proxy communication between nginx and postfix doesn't need encryption, so I should disable encryption once I start configuring that proxy using smtpd_use_tls=no, right?

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