esmtp moduleesmtpacceptmailfor,esmtpacceptmailfor.dat - lists domains whose
mail we accept.
esmtpgreeting - what smtpd announces as its greeting.
esmtphelo - what to announce in my HELO command. Defaults to
me.
esmtppercentrelay.dat - a GDBM database file. If address
<user%foo@bar> is given, foo must be in percenthack as the
key. Which is then rewritten by smtpd as <user@val>, where
val is the value of that key in the GDBM file, which can be created by
makegdbm.
esmtproutes - If the host being delivered to is found in this
file, the value will be used instead of looking up MX or A records. The value
is a space/tab separated list of IP addresses or hostnames.
esmtptimeout - general STMP timeout, in seconds. Both smtpd,
and the output module will stop after waiting the specific amount for a
response from the remote server.
rewritedel - if domain is of the form foo@bar, accept delivery
for host bar, user foo@bar.
Rewrite functions:
esmtp - compile-time options may be used to specify various
kinds of behavior when envelope recipient is being rewritten by submit,
including: check for mailbox validity - this involves simply locating any
loaded rewritedel function, and failing otherwise (!); or forking and running
an external filter!
courieresmtpd is typically invoked by couriertcpd to handle incoming connections. courieresmtpd is a full-fledged ESMTP server. courieresmtpd reads ESMTP commands and runs submit to process incoming messages.
courieresmtpd reads BOFHNOEXPN and BOFHNOVRFY environment variables to disable the EXPN and VRFY commands.
The output module reads esmtproutes to check for any hardcoded smarthosts.