I am trying to setup procmail as a mail delivery agent (MDA) for postfix. I understand that I should use the mailbox_command option in postfix for this, but an internet search revealed contradicting advice on how exactly to do this:
Several sources suggest to just use
mailbox_command = /usr/bin/procmailSome sources suggest using the
-foption, e.g. as inmailbox_command = /usr/bin/procmail -f-See for example here. This seems to adjust the date in From lines.
Some sources suggest using procmail in "delivery mode", i.e. using the
-doption:mailbox_command = /usr/bin/procmail -d ${USER}
(There are many variations of these three approaches, e.g. using -a to pass information to the procmail recipes or setting MAILDIR.)
What are the advantages and disadvantages of the three approaches? And in particular, what is the effect of using "delivery mode"?