On Sun, Dec 29, 2024 at 18:38:10 +0100, Jerome BENOIT wrote: > Second, your SMTP may allow to specify the port you desire to use. This the > case with exim4.
You can listen on any port you like, but if people want to send email to you, they will try to connect to you on TCP port 25. There is no provision in SMTP for a variable port number. The only way a variable port number would be useful is if you're part of an isolated group of senders who have all elected to use an alternative port when talking to each other. The rest of the world will not be able to send to you.
