README for 8.9.1a-envto+etrnprog.dif

			Version 1.0 20-Oct-1998


0. INTRODUCTION

  This patch really does two things:

   1. The original Envelope-To information is saved for each
      adressee and can be added as a header at final (local) delivery
      Envelope-To address during delivery.
   2. A new option is introduced, EtrnProg, that defines a program
      to be executed at ETRN time instead of sendmail handling
      it internally.

1. NEW OPTION: EnvelopeToHeader

1.1 WHAT IS IT

  If this option is set, a header with the name of this option and
  the value of the Envelope-To address is added if final (local)
  delivery is performed. It is useful to add an Envelope-To header
  line to locally delivered mail so that all mail for a domain can
  be dumped into a local mailbox for retrievement with POP3 without
  the loss of Envelope-To information.

1.2 USAGE

  Example to add an X-Envelope-To header to all locally delivered mail:

   a. You need to turn off the `m' flag in sendmail.cf for the mailer
      that does local delivery, usually Mlocal. You don't want the
      Envelope-To information to be shared between unrelated accounts.
      In fact sendmail will ensure that the Envelope-To header doesn't
      get added for local mailers with the `m' flag turned on.

   b. You have to turn on the EnvelopeToHeader option by adding
      the following to the option list in sendmail.cf:

      # Add X-Envelope-To to locally delivered mail
      O EnvelopeToHeader=X-Envelope-To

      If you are using the m4 stuff to generate the sendmail.cf file,
      you can add this under the LOCAL_CONFIG macro:

      LOCAL_CONFIG
      # Add X-Envelope-To to locally delivered mail
      O EnvelopeToHeader=X-Envelope-To

1.3 CHANGES TO THE QUEUE FILE FORMAT

   The standard queue file now has an extra field called `Y'. In the
   queue file, multiple `Y' lines may be present before the `R' line
   that defines a recipient. The `Y' line defines an original recipient,
   all Y lines together are the Envelope-To information for this
   new (local) recipient.

2. NEW OPTION: EtrnProg

  If you somehow deliver queued SMTP mail in another way than usual,
  you need to intercept the ETRN command. If the option EtrnProg is
  set, sendmail will execute that program upon receiving the ETRN
  command. To define the EtrnProg option, see the above example of
  how to define the EnvelopeToHeader.

  The EtrnProg program will be executed with 2 arguments:

  /path/to/etrnprog  {ip number of client} {argument to the ETRN command}

  This sample perl script duplicates the functionality of the internal
  ETRN command:

    #! /usr/bin/perl

    $arg = $ARGV[1];
    # The sendmail implementation of the -qR option and the ETRN
    # part of the RFC don't agree about the @ sign
    if ($arg =~ m/^@/) {
	$arg =~ s/^@//;
    } else {
	$arg = "@" . $arg;
    }

    exec("/usr/sbin/sendmail", "-qR$arg");



	20-Oct-1998   Miquel van Smoorenburg  <miquels@cistron.nl>