.TH qmail-smtpd 8
.SH NAME
qmail-smtpd \- receive mail via SMTP
.SH SYNOPSIS
.B qmail-smtpd
.SH DESCRIPTION
.B qmail-smtpd
receives mail messages via the Simple Mail Transfer Protocol (SMTP)
and invokes
.B qmail-queue
to deposit them into the outgoing queue.
.B qmail-smtpd
must be supplied several environment variables;
see
.BR tcp-environ(5) .

.B qmail-smtpd
is responsible for counting hops.
It rejects any message with 100 or more 
.B Received
or
.B Delivered-To
header fields.

.B qmail-smtpd
supports ESMTP, including the 8BITMIME and PIPELINING options.
.SH TRANSPARENCY
.B qmail-smtpd
converts the SMTP newline convention into the UNIX newline convention
by converting CR LF into LF.
It returns a temporary error and drops the connection on bare LFs;
see
.BR http://pobox.com/~djb/docs/smtplf.html .

.B qmail-smtpd
accepts messages that contain long lines or non-ASCII characters,
even though such messages violate the SMTP protocol.
.SH "CONTROL FILES"
.TP 5
.I badmailfrom
Unacceptable envelope sender addresses.
.B qmail-smtpd
will reject every recipient address for a message
if the envelope sender address is listed in
.IR badmailfrom .
A line in
.I badmailfrom
may be of the form
.BR @\fIhost ,
meaning every address at
.IR host .
.TP 5
.I databytes
Maximum number of bytes allowed in a message,
or 0 for no limit.
Default: 0.
If a message exceeds this limit,
.B qmail-smtpd
returns a permanent error code to the client;
in contrast, if
the disk is full or
.B qmail-smtpd
hits a resource limit,
.B qmail-smtpd
returns a temporary error code.

.I databytes
counts bytes as stored on disk, not as transmitted through the network.
It does not count the
.B qmail-smtpd
Received line, the
.B qmail-queue
Received line, or the envelope.

If the environment variable
.B DATABYTES
is set, it overrides
.IR databytes .
.TP 5
.I localiphost
Replacement host name for local IP addresses.
Default:
.IR me ,
if that is supplied.
.B qmail-smtpd
is responsible for recognizing dotted-decimal addresses for the
current host.
When it sees a recipient address of the form
.IR box@[d.d.d.d] ,
where
.I d.d.d.d
is a local IP address,
it replaces
.IR [d.d.d.d]
with
.IR localiphost .
This is done before
.IR rcpthosts .
.TP 5
.I morercpthosts
Extra allowed RCPT domains.
If
.I rcpthosts
and
.I morercpthosts
both exist,
.I morercpthosts
is effectively appended to
.IR rcpthosts .

You must run
.B qmail-newmrh
whenever
.I morercpthosts
changes.

Rule of thumb for large sites:
Put your 50 most commonly used domains into
.IR rcpthosts ,
and the rest into
.IR morercpthosts .
.TP 5
.I rcpthosts
Allowed RCPT domains.
If
.I rcpthosts
is supplied,
.B qmail-smtpd
will reject
any envelope recipient address with a domain not listed in
.IR rcpthosts .

Exception:
If the environment variable
.B RELAYCLIENT
is set,
.B qmail-smtpd
will ignore
.IR rcpthosts ,
and will append the value of
.B RELAYCLIENT
to each incoming recipient address.

.I rcpthosts
may include wildcards:

.EX
   heaven.af.mil
   .heaven.af.mil
.EE

Envelope recipient addresses without @ signs are
always allowed through.
.TP 5
.I smtpgreeting
SMTP greeting message.
Default:
.IR me ,
if that is supplied;
otherwise
.B qmail-smtpd
will refuse to run.
The first word of
.I smtpgreeting
should be the current host's name.
.TP 5
.I timeoutsmtpd
Number of seconds
.B qmail-smtpd
will wait for each new buffer of data from the remote SMTP client.
Default: 1200.
.SH "RECIPIENT VERIFICATION"
Recipient verification is enabled with the
.B VERIFY
environment variable. This can be used to specify per-recipient
rejection of invalid recipient addresses (immediate verification
causing a permanent 550 error response to the RCPT command),
or deferred rejection at DATA time (554 response) of the whole
session if any recipient addresses don't exist.

To verify an address,
.B qmail-smtpd
uses a separate
.B qmail-verify
UDP server. By default this will be on the loopback address 127.0.0.1,
port 11113. Enable verification like this,

.EX
   VERIFY=":"

   VERIFY="DEFER"
.EE

(for immediate, deferred verification respectively). A different IP
address and/or port can be specified for
.B qmail-verify
as in these examples,

.EX
   VERIFY="192.168.1.1"
   VERIFY=":10101"
   VERIFY="DEFER,:10101"
   VERIFY="DEFER,192.168.1.1:10101"
.EE

Recipient verification may be explicitly disabled by setting
.B VERIFY
to an empty string,

.EX
   VERIFY=""
.EE

Addresses with domains appearing in
.B control/rcpthosts
but not in
.B control/locals
or
.B control/virtualdomains
will be considered valid, reflecting qmail's standard behaviour.
.P
Note that if the environment variable
.B RELAYCLIENT
is set, no checking is carried out.
.P
.B qmail-verify
needs to be running to respond to recipient
verification queries. If no
.B qmail-verify
response is received a temporary 451 error response is
given to the remote system and the session terminated.
.SH "SEE ALSO"
tcp-env(1),
tcp-environ(5),
qmail-control(5),
qmail-inject(8),
qmail-newmrh(8),
qmail-queue(8),
qmail-remote(8),
qmail-verify(8)