## 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.