Mailfront

Backend: qmail

Features:

• The qmail home directory is compiled into the program, and defaults to /var/qmail, but may be overridden by $QMAILHOME.
• Messages are delivered through the executable named in $QMAILQUEUE, or $QMAILHOME/bin/qmail-queue if it is not set.
• If qmail-queue exits non-zero, the qmail backend looks for an error message in $QQERRMSG_#, where # is the exit code of qmail-queue. As usual, exit codes between 11 and 40 indicate permanent errors, and all others indicate temporary errors.
• The qmail-queue PID is logged in success messages for correlation with the qmail logs.