Can you run qmail on a non-standard port?

If you have used the Life With Qmail installation method this is quite easy.

You would edit the smtpd start-up file found at:

/var/qmail/supervise/qmail-smtpd/run

If you wanted your server to answer on port 26 instaed of 25 then you would make the following changes:

Replace:

/usr/local/bin/tcpserver -v -R -l "$LOCAL" -x /etc/tcp.smtp.cdb -c "$MAXSMTPD" \

-u "$QMAILDUID" -g "$NOFILESGID" 0 smtp /var/qmail/bin/qmail-smtpd 2>&1

With:

/usr/local/bin/tcpserver -v -R -l "$LOCAL" -x /etc/tcp.smtp.cdb -c "$MAXSMTPD" \

-u "$QMAILDUID" -g "$NOFILESGID" 0 26 /var/qmail/bin/qmail-smtpd 2>&1