How to Configure alternative SMTP port in Qmail (Linux + Plesk)


Most of the ISP blocks default SMTP port (25) to control mail flow hence it is always advisable to have additional SMTP port open on the server. Here are the steps to configure qmail to use alternate SMTP port 587 on Linux Plesk server.

1. Login to the shell with root user and go to “xinetd.d” directory

[root@server]# cd /etc/xinetd.d

2. [root@server]# cat smtp_psa

3. [root@server]# vi /etc/services

Add below lines in “/etc/services” file
smtp_psa_new 587/tcp mail
smtp_psa_new 587/udp mail

4. [root@server]# cp smtp_psa smtp_psa_new

5. Change the service line in the new file “smtp_psa_new” to be this:

service smtp_psa_new
socket_type = stream
protocol = tcp
wait = no
disable = no
user = root
instances = UNLIMITED
server = /var/qmail/bin/tcp-env
server_args = /usr/sbin/rblsmtpd -r /var/qmail/bin/relaylock /var/qmail/bin/qmail-smtpd /var/qmail/bin/smtp_auth /var/qmail/bin/true /var/qmail/bin/cmd5checkpw /var/qmail/bin/true

6. [root@server]#/etc/init.d/xinetd restart

7. Make sure that additional port 587 is open in firewall and check whether port is now listening by following command:

[root@server]# netstat -anp | grep xinetd
It should display the output as given below
tcp 0 0* LISTEN 6989/xinetd
tcp 0 0* LISTEN 6989/xinetd

That’s it !!! Enjoy

Vishwajit Kale

Vishwajit Kale blazed onto the digital marketing scene back in 2015 and is the digital marketing strategist of Hostripples, a company that aims to provide affordable web hosting solutions. Vishwajit is experienced in digital and content marketing along with SEO. He's fond of writing technology blogs, traveling and reading.