NAME

       qmail-smtpd - receive mail via SMTP

SYNOPSIS

       qmail-smtpd

DESCRIPTION

       qmail-smtpd  receives  mail  messages  via  the  Simple  Mail Transfer Protocol (SMTP) and
       invokes qmail-queue to deposit them into the outgoing queue.  qmail-smtpd must be supplied
       several environment variables; see tcp-environ(5).

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

       qmail-smtpd supports ESMTP, including the 8BITMIME and PIPELINING options.

TRANSPARENCY

       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 http://pobox.com/~djb/docs/smtplf.html.

       qmail-smtpd accepts messages that contain long lines or non-ASCII characters, even  though
       such messages violate the SMTP protocol.

CONTROL FILES

       badmailfrom
            Unacceptable  envelope  sender  addresses.   qmail-smtpd  will reject every recipient
            address for a message if the envelope sender address is  listed  in  badmailfrom.   A
            line in badmailfrom may be of the form @host, meaning every address at host.

       databytes
            Maximum  number  of bytes allowed in a message, or 0 for no limit.  Default: 0.  If a
            message exceeds this limit, qmail-smtpd returns a permanent error code to the client;
            in  contrast,  if  the disk is full or qmail-smtpd hits a resource limit, qmail-smtpd
            returns a temporary error code.

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

            If the environment variable DATABYTES is set, it overrides databytes.

       localiphost
            Replacement host name for local IP addresses.  Default:  me,  if  that  is  supplied.
            qmail-smtpd  is  responsible for recognizing dotted-decimal addresses for the current
            host.  When it sees a recipient address of the form box@[d.d.d.d], where d.d.d.d is a
            local  IP  address,  it  replaces  [d.d.d.d]  with  localiphost.  This is done before
            rcpthosts.

       morercpthosts
            Extra allowed RCPT domains.  If rcpthosts and morercpthosts both exist, morercpthosts
            is effectively appended to rcpthosts.

            You must run qmail-newmrh whenever morercpthosts changes.

            Rule of thumb for large sites: Put your 50 most commonly used domains into rcpthosts,
            and the rest into morercpthosts.

       rcpthosts
            Allowed RCPT domains.  If rcpthosts is supplied, qmail-smtpd will reject any envelope
            recipient address with a domain not listed in rcpthosts.

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

            rcpthosts may include wildcards:

               heaven.af.mil
               .heaven.af.mil

            Envelope recipient addresses without @ signs are always allowed through.

       smtpgreeting
            SMTP  greeting message.  Default: me, if that is supplied; otherwise qmail-smtpd will
            refuse to run.  The first word of smtpgreeting should be the current host's name.

       timeoutsmtpd
            Number of seconds qmail-smtpd will wait for each new buffer of data from  the  remote
            SMTP client.  Default: 1200.

RECIPIENT VERIFICATION

       Recipient  verification  is enabled with the 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, qmail-smtpd uses a separate qmail-verify UDP server. By default this
       will be on the loopback address 127.0.0.1, port 11113. Enable verification like this,

          VERIFY=":"

          VERIFY="DEFER"

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

          VERIFY="192.168.1.1"
          VERIFY=":10101"
          VERIFY="DEFER,:10101"
          VERIFY="DEFER,192.168.1.1:10101"

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

          VERIFY=""

       Addresses with domains  appearing  in  control/rcpthosts  but  not  in  control/locals  or
       control/virtualdomains will be considered valid, reflecting qmail's standard behaviour.

       Note that if the environment variable RELAYCLIENT is set, no checking is carried out.

       qmail-verify  needs  to  be  running  to  respond to recipient verification queries. If no
       qmail-verify response is received a temporary 451 error response is given  to  the  remote
       system and the session terminated.

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)

                                                                                   qmail-smtpd(8)