How To Use Postfix Without Third Party Relay Service

Posted on March 10, 2020

Ubuntu 18.04

DigitalOcean Cloud Firewalls

Cloud Computing

By rishi008

I want to use postfix as send only smtp without any third party relay such as gmail :- https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-postfix-as-a-send-only-smtp-server-on-ubuntu-16-04

But many cloud providers block port 25. Is there any way to make work postfix on port 587?

Tried editing postfix configs but not worked.

Thanks

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KFSys

March 10, 2020

Hi @rishi008,

You should be able to easily change the port from 25 to 587. You can follow the article you’ve provided to actually install Postfix.

As soon as you do, can do the following to enable port 587 using Postfix.

Before we start, here is some information that might confuse people if it’s not mentioned. Normally, everyone uses port 25 as it is the default port in emails. As it is extensively used by many, it conveys malware and spam. So most of the ISPs are filtering the emails coming through it.

Port 587 is another submission port as 25. This port ensures that the emails are submitted securely. Thus, most of the ISPs don’t block this port. This definitely reduces the rate of rejected messages on the server.

Now onto the configuration.

Once you have installed Postfix, open your master.cf file