Provided by: mailfront_0.98-1_i386 bug

NAME

       smtpfront - SMTP Front Ends

SYNOPSIS

       smtpfront

DESCRIPTION

       The  code  for  SMTP is divided internally into two sections: front-end
       and back-end code.  The front-end code handles the low-level details of
       the  protocol.   The  back-end code handles the validation and delivery
       details in a protocol-independant fashion.

FEATURES

       The following features are common to all SMTP front-ends:

       o Validates  senders  and   recipients   according   to   ‘‘mailrules’’
         processing.

       o If  $RELAYCLIENT is set, all recipient addresses not rejected by mail
         rules are allowed, and its contents are appended  to  each  recipient
         address.  Back-end validation is omitted.

       o Handles  RFC  2554  SMTP  authentication.   After  authentication all
         recipients not rejected by  mail  rules  are  allowed,  and  back-end
         validation is omitted.

       o Automatically  handles either bare NL or RFC 821/2821 compliant CR/NL
         end-of-line conventions.

       o Rejects messages that exceed $DATABYTES bytes in the body.

       o Times out connections after $TIMEOUT seconds of inactivity  (defaults
         to 1200 seconds or 20 minutes), or $SESSION_TIMEOUT seconds after the
         connection was established (defaults to 86400 seconds or 24 hours).

       o Counts the number of "Received:"  and  "Delivered-To:"  headers,  and
         rejects  the  message  if  more  than  $MAXHOPS  of  either  are seen
         (defaults to 100).

       o All error responses are logged.

       o Handles (ignores) RFC 1869 extended parameters on  the  ‘‘RCPT  TO:’’
         and ‘‘MAIL FROM:’’ commands.

       o Initial greeting message is configureable by $SMTPGREETING.

       o Rejects bounce messages (messages with an empty envelope sender) that
         attempt to deliver to multiple recipients.

       o Optionally adds a  fixup  "Received:"  header  for  hosts  that  have
         different    incoming   and   outgoing   hostnames   or   IPs.    Set
         $FIXUP_RECEIVED_HOST and $FIXUP_RECEIVED_IP if you want  this  header
         added.

BACK ENDS

       smtpfront-echo
              Uses  the  echo  backend  to  simply  echo  back  the sender and
              recipient parameters, and the size of the data to the client.

       smtpfront-qmail
              Uses the ‘‘qmail validation features’’  to  validate  addresses,
              and the ‘‘qmail backend’’ to deliver messages.

       smtpfront-reject
              If  $SMTPREJECT is set, all SMTP commands are rejected with this
              message.  If the message starts with a "-",  a  permanent  error
              number  is used and the leading "-" is stripped.  If $SMTPREJECT
              is not set, it execs its command line.

SEE ALSO

       pop3front(8)

        /usr/share/doc/mailfront/html/mailrules.html
        /usr/share/doc/mailfront/html/qmail-validate.html
        /usr/share/doc/mailfront/html/qmail-backend.html

        http://untroubled.org/mailfront/

                                                                  smtpfront(8)