To SMTP-authenticate users without patching ofmipd(8) or qmail-smtpd(8),
compose the following programs into your configuration:

- reup runs a program repeatedly until it succeeds.
- authup offers SMTP or POP3 authentication and calls checkpassword.
- checknotroot refuses to run as UID 0.
- fixsmtpio filters SMTP I/O and exit status to suit authup.

authup and fixsmtpio can also offer STARTTLS for message submission and
incoming SMTP, respectively.