I have several mail servers that are used for mailings via SMTP. I use Postfix+Opendkim+Dovecot. Websites for sending letters connect to SMTP servers on port 587.

I look at the sending logs and letters from the SMTP server are sent to gmail, yahoo, icloud and so on on port 25.

Is it possible to make Postfix send letters to mail servers on port 587? There is a lot of information on the Internet on how to force Postfix to accept letters on port 587, but I did not find clear information on how to send on port 25.

Some cloud providers block outgoing traffic on port 25 and offer to send emails on outgoing ports 587 or 465.

Jul 3 11:38:03 smtp postfix/smtp[16580]: ABDB4C06AA: to=<[email protected]>, relay=gmail-smtp-in.l.google.com**[64.233.164.27]:25**, delay=0.5, delays=0.07/0/0.17/0.27, dsn=2.0.0, status=sent (250 2.0.0 OK 1719995883 38308e7fff4ca-2ee51546c65si28040131fa.331 - gsmtp)

I tried to uncomment the parameters for submission inet n - y - - smtpd in the file /etc/postfix/master.cf, but this is for incoming connections to the SMTP server on port 587, and not outgoing to port 587