I am trying to use plesk as a mail server, so IMAP and Webmail, but want all my outgoing mail to go through a 3rd party SMTP Service who filter our incoming mail also. I am getting mixed thoughts online as to whether you can do this. I know that on the plesk CP you have to select either SMTP relay or use postfix, but is it possible to modify the config in postfix to use as a full email server but also relay all outgoing mail to another server?