Plesk: How to switch from Qmail to Postfix and vice versa

There are two MTA that are supported by Plesk since version 9:
– Qmail
– Postfix

You can change the MTA using the autoinstaller script of Plesk:

# /usr/local/psa/bin/autoinstaller

On the 4th page select the currently installed Plesk version. Disable all other applications.
On the Main components list page select the MTA you want to use and click enter to complete the installation.

It is also possible to change the MTA without running the autoinstaller interface:
To switch from Qmail to Postfix:

# /usr/local/psa/admin/sbin/autoinstaller –select-release-current –install-component postfix

To switch from Postfix to Qmail:

# /usr/local/psa/admin/sbin/autoinstaller –select-release-current –install-component qmail