Sometimes it happens that port 25 is blocked by your ISP and you need port 26 to be enabled on the server for mails.
Follow the below steps to enable port 26 on your linux server with Postfix MTA(Mail Transfer Agent) :
Open the /etc/postfix/master.cf file
[email protected][#] vi /etc/postfix/master.cf
and then search for the line :
smtp inet n – n – – smtpd
and this line below the above one
26 inet n – n – – smtpd
Save and Quit (wq!)
And finally restart the Postfix service on the Server.
[email protected][#] /etc/init.d/postfix restart
You can test Postfix by connecting on the new port number. Use the terminal command telnet localhost 26 to test your new port number.
Note : Also you need to make sure that the Port 26 is opened in the Server Firewall.
That’s all you are done.