Switch from qmail to Postfix and vice versa in Plesk
There are two Message Transfer Agents (MTA) supported by Parallels Plesk Panel, they are qmail and Postfix. Each time only one of them is used by Parallels Plesk Panel.
MTA that is currently used by Parallels Plesk Panel is shown on the Services management page {Home -> Services Management}:
SMTP Server (Postfix)
or
SMTP Server (qmail)
Also it is possible to check MTA using Plesk utility mailmng:
# $PRODUCT_ROOT_D/admin/sbin/mailmng –features | grep SMTP_Server
features[‘SMTP_Server’] = “Postfix”;
features[‘SMTP_Server_package’] = “postfix”;
or
# $PRODUCT_ROOT_D/admin/sbin/mailmng –features | grep SMTP_Server
features[‘SMTP_Server’] = “QMail”;
features[‘SMTP_Server_package’] = “psa-qmail”;
You can switch MTA from qmail to Postfix and vice versa using autoinstaller script.
Run the script without parameters
# /usr/local/psa/bin/autoinstaller
and select Parallels Plesk Panel 9 (currently installed) on the fourth page. Disable all other applications like SSO and Sitebuilder.
On page Main components list for Plesk select Qmail or Postfix mailserver and click Enter to complete the installation.
Alternatively you may run the following command to switch MTA to Postfix:
# /usr/local/psa/admin/sbin/autoinstaller –select-release-current –install-component postfix
and for switching to Qmail:
# /usr/local/psa/admin/sbin/autoinstaller –select-release-current –install-component qmail
Additional information
Location of mail maildirs ($PLESK_MAILNAMES_D) and mail format is not changed when MTA is switched. Old mail messages remain unchanged and are available.
However mail queue is reconfigured during switching MTA, all messages that are still in queue are lost. Before switching it is recommended to stop current MTA and process the queue, then do the switching.