Enabling port 587 in Postfix is really easy.

Port 587 ensures the security of the emails while sending them. Therefore, it reduces the rejected emails on the server.

At Bobcares, we receive requests to enable the ports on postfix and fix its errors as a part of our Server Management Services.

Today, let’s see how our Support Engineers enable this port on Postfix and fix its errors.

What is the importance of port 587 in postfix?

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.

Also, they sometimes block port 25. In that case, the best solution is to enable the 587 port.

Port 587 is another submission port. 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.

Thus, this is mainly helpful in sending bulk emails.

How we enable port 587 in postfix?

Till now we have discussed why 587 port is necessary in the email servers. Let’s now see how our Support Engineers enable it on the server.

Enable port 587 in postfix from server

To open the submission port our Support Engineers edit the file master.cf to enable 587 port.

We edit this file using the below command.

vi /etc/postfix/master.cf

And then we remove the # symbol in front of the line:

#submission inet n - n - - smtpd

So, after editing it looks like this:

submission inet n - n - - smtpd

After that, we restart the postfix using the below command.

service postfix restart

This will finally enable the port 587 in postfix.

Enable port 587 in postfix from Plesk

We can enable port 587 from the Plesk panel. Let us discuss how our Support Engineers enable it for our customers.

Login to Plesk from an administrator account.

Now go to Tool & Setting and select Mail Server Setting.

We check the box Enable SMTP service on port 587 on all IP addresses.

For server will Plesk. We login to the server and use the command to port submission ports.

/usr/local/psa/bin/mailserver --set-message-submission true

Errors with port 587 in Postfix

Let us discuss the common error faced by our customers using port 587.

Port not open

Recently one customer contacted us saying he has enabled port 587 in master.cf still mail configuration fails.

On analyzing the server the submission entry was present in master.cf file. But port 587 was not open in the firewall.

So we open port 587 in the server.

iptables -I INPUT -p tcp -m tcp --dport 587 -j ACCEPT
service iptables save

The command changes based on the firewall used.

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Conclusion

In short, the port 587 securely sends emails in postfix and thus reduces the spam emails. Today, we saw how our Support Engineers enable this port in Postfix and fix its related errors.