How to change smtp port 25 to port 587

[khampasith]

Hello
My ISP is blocked port 25 to send mail and I want to change default port 25 to port 587, How to change?
Thank you
Best regards

[troeder]

Please describe the scenario.
Do you want to send or receive email?
In UCS, when the mail server app is installed, port 587 is open by default.

[ahrnke]

I guess that the question is related to the relayhost setting.
Postfix Small/Home Office Hints and Tips says:

The relayhost destination may also specify a non-default TCP port. For example, the alternative form [mail.isp.example]:submission tells Postfix to connect to TCP network port 587, which is reserved for email client applications.

I havent verified it, but it looks like adjusting UCRV “mail/relayhost” is the way to go.

cheers,
Dirk

[khampasith]

Thank all I just tell ISP to unblock port 25 and then it work can send email with port 25