rfc1429.txt

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Network Working Group                                          E. Thomas
Request for Comments: 1429                    Swedish University Network
                                                           February 1993


                      Listserv Distribute Protocol

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard.  Distribution of this memo is
   unlimited.

Abstract

   This memo specifies a subset of the distribution protocol used by the
   BITNET LISTSERV to deliver mail messages to large amounts of
   recipients.  This protocol, known as DISTRIBUTE, optimizes the
   distribution by sending a single copy of the message over heavily
   loaded links, insofar as topological information is available to
   guide such decisions, and reduces the average turnaround time for
   large mailing lists to 5-15 minutes on the average. This memo
   describes a simple interface allowing non-BITNET mailing list
   exploders (or other bulk-delivery scripts) to take advantage of this
   service by letting the BITNET distribution network take care of the
   delivery.

Introduction

   Running a mailing list of 1,000 subscribers or more with plain
   "sendmail" while keeping turnaround time to a reasonable level is no
   easy task. Due mostly to its limited bandwidth in the mid-80's,
   BITNET has developed an efficient bulk delivery protocol for its
   mailing lists. Originally introduced in 1986, this protocol was
   refined little by little and now carries 2-6 million mail messages a
   day. In fact, this distribution mechanism implements a general-
   purpose delivery service which can be used by any user of BITNET or
   the Internet. Thus, a simple solution to the "sendmail" turnaround
   problem is to wrap the message and recipient list in a DISTRIBUTE
   envelope and pass it to a BITNET server for delivery.  This may not
   be the best possible solution, but it has the advantage of being easy
   to implement.

   In this document we will use the term "production" to refer to the
   normal operation of the mailing list (or bulk delivery application)
   you want to pipe through the DISTRIBUTE service. That is, the
   "production" options are those you should specify once everything is
   tested and you are confident that the setup is working to your



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RFC 1429              Listserv Distribute Protocol         February 1993


   satisfaction. In contrast, "test" and "debug" options can be used to
   experiment with the protocol but should not be used for normal
   operation because of the additional bandwidth and CPU time required
   to generate the various informational reports.

   Finally, it should be noted that the DISTRIBUTE protocol was
   developed to address a number of issues, some of them relevant only
   to BITNET, and has evolved since 1986 while keeping a compatible
   syntax. For the sake of brevity, this RFC describes only a small
   subset of the available options and syntax. This is why the syntax
   may appear unnecessarily complicated or even illogical.

1. Selecting an entry point into the DISTRIBUTE backbone

   The first thing you have to do is to find a suitable site to submit
   your distributions to. For testing, and for testing ONLY, you can
   use:

                         [e-mail]

   For production use, however, you should select a DISTRIBUTE site in
   your topological vicinity: it would make no sense to pass your
   distributions from California to a server in Sweden if most of your
   recipients are in the US. If your organization is connected to BITNET
   and your BITNET system is part of the DISTRIBUTE backbone, this ought
   to be your best bet. Otherwise you will want to contact someone
   knowledgeable about BITNET (or the author of this RFC if you have no
   BITNET users). Make sure to run through the following checklist
   before sending any production traffic to the site in question:


   a. Do you have good connectivity to the host in question? Does the
      host, in general, have decent BITNET connectivity? There are still
      a few sites that insist on using 9.6k leased lines for BITNET in
      spite of having T1 IP access. You will want to avoid them.

   b. Send mail to the server with "show version" in the message body
      (not in the subject field, which is ignored). Is the server running
      version 1.7f or higher? If so, it should not have given you the
      following warning,

        >>> This server is configured to use PUNCH format for mail <<<

      which means that messages with lines longer than 80 characters
      cannot be handled properly. If the software version is less than
      1.7f, the warning will not be present; instead, check the first
      (bottom) "Received:" field. If it does not say "LMail", do not use
      this server as it probably cannot handle messages with long lines.



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RFC 1429              Listserv Distribute Protocol         February 1993


      Finally, make sure that the "Master nodes file" is not older
      than 2 months: there are a handful of sites which never update
      their tables due to staffing problems. They cannot be prevented
      from running LISTSERV, but you will certainly want to avoid them.

   c. How big is your workload? If you are planning to use the service
      for more than 10,000 daily recipients, you should get permission
      from the LISTSERV administrator, both as a matter of courtesy and
      to hear about any restrictions or regularly scheduled downtime they
      might have. For instance, some universities might not allow large
      distributions during prime time, or they may have several
      DISTRIBUTE machines and will want to make sure you use the "right"
      one.  Send mail to "owner-listserv" at the host in question and
      give an estimate of the amount of daily messages and recipients you
      would like to submit. If your message bounces back with "No such
      local user" or the like, it means the server did not pass the above
      test (b) and you don't want to use it anyway.

   An index of sites/hosts which have the required configuration, good
   connectivity, keep their tables up to date and have generally agreed
   to provide this service to anyone in their topological area will be
   published separately in the future.

2. Physical delivery of the DISTRIBUTE request

   The distribution request is delivered via SMTP to the e-mail address
   obtained in step 1 (for instance, [e-mail]). In fact,
   as long as you can somehow get mail to the server's host, you can use
   the service; SMTP is just the most convenient way of doing so.

2.1. Contents of MAIL FROM: field

   You should set the MAIL FROM: field to the address of the person who
   maintains your mailing list or, generally speaking, to the address of
   a human being who can take action in case the message fails to reach
   the DISTRIBUTE server's host. This is a very rare occurrence.

2.2. Contents of RCPT TO: field

   The RCPT TO: field points to the server's address (for instance,
   [e-mail]).

2.3. Contents of the RFC822 header

   After the DATA instruction, you must supply a valid RFC822 header
   with a "From:" field pointing to the mailbox that should receive
   notification of delivery problems, bounced mail, and so on. This can
   be the same as the MAIL FROM: field, an address of the type "owner-



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RFC 1429              Listserv Distribute Protocol         February 1993


   xxxx@yourhost", etc.  DO NOT PUT THE LIST SUBMISSION ADDRESS THERE,
   or you will get mailing loops.

   For testing, the "From:" field should point to your own mailbox, so
   that you get the responses from the server.

   As long as RFC822 syntax is respected, the only field that matters is
   the "From:" field (or "Sender:", "Resent-From:", etc.). In practice
   this means you can just pipe the distribution request into "mail
   listserv@whatever" and let your mail program build all the headers.

3. Format of the DISTRIBUTE request

   The body of the message delivered to LISTSERV defines the recipients
   of the distribution and the text (header + body) of the RFC822
   message you want to have delivered. The request starts with a "job
   card", followed by a DISTRIBUTE command, a list of recipients, and
   finally the message header and body.

3.1. Syntax of the JOB card

   The purpose of the JOB card is to make sure that any spurious text
   inserted by mail gateways or the like is flushed and not erroneously
   interpreted as a command. It can optionally be used to associate a
   "job name" with the request, in case you want to use tools to assist
   you in processing the notifications you get from the DISTRIBUTE
   servers when running in test mode. The syntax is as follows:

   //jobname JOB ECHO=NO

   "jobname" can be anything as long as it does not contain blanks, and
   can be omitted. LISTSERV generally ignores case when parsing
   commands, so you can use "job" or "Job" if you prefer. The ECHO=NO
   keyword is required for production use, to suppress the "resource
   usage summary" you would otherwise get upon completion of your
   delivery. You may want to omit it when testing.

3.2. Syntax of the DISTRIBUTE command

   Below the JOB card, you must supply the following line:

   DISTRIBUTE MAIL

   For production mode, do not specify anything else on that line. When
   testing, you should add ACK=MAIL in order to get an acknowledgement
   confirming the delivery. There are two other useful options:
   DEBUG=YES, which instructs the server to produce a report showing how
   the various recipients will be routed, but without actually



Thomas                                                          [Page 4]