We can check currently using MTA from the Services Management page at Home > Services Management:
- SMTP Server (Postfix)
- SMTP Server (QMail)
Also, we can check the MTA using the Plesk utility through the command line:
# plesk sbin mailmng-server --features | grep SMTP_Server
or
# plesk sbin mailmng-server --features | grep SMTP_Server
MTA can be switched from QMail to Postfix and back using the auto installer script and command line.
Via Plesk UI:
Select QMail or Postfix SMTP server under Mail hosting section in Plesk > Tools & Settings > Updates and Upgrades > Add/Remove Components
Via command line:
- To switch the MTA to Postfix:
# plesk installer --select-release-current --install-component postfix
- To switch the MTA to QMail:
# plesk installer --select-release-current --install-component qmail
Alternatively, we can change the MTA by running the below command:
# plesk installer
Follow instructions and select QMail or Postfix SMTP server under Mail hosting section.
Additional Information
Before switching, it is recommended you wait until all queued emails are delivered and stop the SMTP service to stop receiving emails.