courieresmtpd - Courier mail server ESMTP daemon
The actual Courier ESMTP daemon (mail transfer agent) is called
courieresmtpd. Normally, courieresmtpd is run from couriertcpd, which
is in turn run from esmtpd start or a similar command. You should not
have to run courieresmtpd manually.
couriertcpd(8), esmtpd(8).