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  The Linux Electronic Mail Administrator HOWTO
  Guylhem Aznar <guylhem at metalab.unc.edu>
  v3.2, January 2000

  This document describes the setup, care and feeding of Electronic Mail
  (e-mail) under Linux.  It is primarily intended for administrators,
  rather than users.  (See the Mail-User's-HOWTO for information on user
  issues and user agents.)  You need to read this if you plan to commu�
  nicate locally or to remote sites via electronic mail.  You probably
  do *not* need to read this document if don't exchange electronic mail
  with other users on your system or with other sites.
  ______________________________________________________________________

  Table of Contents



  1. Introduction, copyright and standard disclaimer

     1.1 Email and spamming
     1.2 Goals
     1.3 New versions
     1.4 Feedback
     1.5 Copyright
     1.6 Limited warranty

  2. Other sources of information

     2.1 Mail User's HOWTO There is a Mail User's HOWTO, which focuses on user issues. It is currently maintained by Eric S. Raymond; you should be able to view it on the World Wide Web at
     2.2 USENET
     2.3 Mailing Lists
     2.4 Other documents from LDP
     2.5 Books

  3. How Electronic Mail Works

     3.1 Mail between full-time Internet machines
     3.2 Notifiers
     3.3 Mail to part-time Internet machines
     3.4 Remote mail and remote-mail protocols
     3.5 Mailbox formats

  4. Requirements

     4.1 Hardware

  5. Choosing a Mail Transport Agent

     5.1 sendmail
     5.2 smail v3.2
     5.3 qmail
     5.4 exim

  6. Installing Transport Software

     6.1 Qmail v1.03
        6.1.1 Getting qmail
        6.1.2 Uncompressing sources
        6.1.3 Preparing for compilation
        6.1.4 Configuring qmail
           6.1.4.1 defaultdomain, me, plusdomain
           6.1.4.2 locals, rcpthosts
           6.1.4.3 virtualdomains
        6.1.5 Testing qmail
        6.1.6 Removing your other MTA
        6.1.7 That's all, folks!
     6.2 Smail v3.1
        6.2.1 Configuring smail
           6.2.1.1 "config" file
           6.2.1.2 "directors" file
           6.2.1.3 "fidopaths" file
           6.2.1.4 "routers" file
           6.2.1.5 "transports" file
           6.2.1.6 "maps/" directory
        6.2.2 Other good examples
        6.2.3 Restarting inetd
        6.2.4 Smail with smtp
     6.3 OUTDATED SECTION: Sendmail+IDA
        6.3.1 Source installation
        6.3.2 The sendmail.m4 file
        6.3.3 Defining a local mailer
        6.3.4 The sendmail+IDA dbm tables
        6.3.5 So which entries are really required?
     6.4 Sendmail 8.x
        6.4.1 A sample 8.7.x mc file
        6.4.2 Sendmail v8 tidbits
     6.5 Local Delivery Agents

  7. User Agent Administration

     7.1 Mutt
     7.2 Elm
     7.3 Mailx

  8. Handling remote mail

     8.1 History
     8.2 Getting mail
     8.3 Sending mail
     8.4 Reading mail
     8.5 Testing
     8.6 Using

  9. Acknowledgements



  ______________________________________________________________________

  1.  Introduction, copyright and standard disclaimer



  1.1.  Email and spamming


  To send mail to anyone mentioned in this document, convert "at" in
  email addresses to "@".

  This conversion is simple for humans, but not spammers' address
  harvesters; therefore it's useful to protect generous contributors
  from being spammed!


  1.2.  Goals


  The intent of this document is to answer some of the questions and
  comments that appear to meet the definition of "frequently asked
  questions" about e-mail software under Linux in general and the
  version in the Linux Debian and RedHat distributions in particular.


  1.3.  New versions


  New versions of this document will be periodically posted to
  comp.os.linux.announce, comp.answers and mail.answers.  They will also
  be added to the various anonymous ftp sites who archive such
  information including sunsite.unc.edu:/pub/Linux/docs/HOWTO.

  In addition, you should be generally able to find this document on the
  Linux WorldWideWeb home page at http://sunsite.unc.edu/mdw/linux.html.


  1.4.  Feedback



  I am interested in any feedback, positive or negative, regarding the
  content of this document via e-mail.  Definitely contact me if you
  find errors or obvious omissions.

  I read, but do not necessarily respond to, all e-mail I receive.
  Requests for enhancements will be considered and acted upon based on
  that day's combination of available time, merit of the request and
  daily blood pressure :-)

  Flames will quietly go to /dev/null so don't bother.

  Feedback concerning the actual format of the document should go to the
  HOWTO coordinator : Tim Bynum (howto at wallybox.cei.net).


  1.5.  Copyright


  The Mail-Administrator HOWTO is copyrighted (c) 1998 Guylhem Aznar.
  Distributed under LDP copyright license.  If you have questions,
  please contact the Linux HOWTO coordinator, at howto at
  wallybox.cei.net.


  1.6.  Limited warranty


  Of course, I disavow any potential liability for the contents of this
  document.  Use of the concepts, examples, and/or other content of this
  document is entirely at your own risk.


  2.  Other sources of information



  2.1.  There is a Mail User's HOWTO, which focuses on user issues.  It
  is currently maintained by Eric S. Raymond; you should be able to view
  it on the World Wide Web at urlnam <http://meta�
  lab.unc.edu/LDP/HOWTO/Mail-User-HOWTO.html>.  Mail User's HOWTO

  2.2.  USENET


  There is nothing special about configuring and running mail software
  under Linux (any more).  Accordingly, you almost certainly do NOT want
  to be posting generic mail-related questions to the comp.os.linux.*
  newsgroups.

  Don't post in comp.os.linux hierarchy unless it's really linux
  specific, for example : "Which options was Debian 1.2 sendmail
  compiled with ?" or "RedHat 5.0 smail crashes when I run it".

  Let me repeat that.

  There is virtually no reason to post anything mail-related in the
  comp.os.linux hierarchy any more.  There are existing newsgroups in
  the comp.mail.* hierarchy to handle *ALL* your questions.

  IF YOU POST TO COMP.OS.LINUX.* FOR NON-LINUX-SPECIFIC QUESTIONS, YOU
  ARE LOOKING IN THE WRONG PLACE FOR HELP.  THE MAIL EXPERTS HANG OUT IN
  THE PLACES INDICATED ABOVE AND GENERALLY DO NOT RUN LINUX.

  POSTING TO THE LINUX HIERARCHY FOR NON-LINUX-SPECIFIC QUESTIONS WASTES
  YOUR TIME AND EVERYONE ELSE'S AND IT FREQUENTLY DELAYS YOUR GETTING
  THE ANSWER TO YOUR QUESTION.
  GOOD PLACES are :

             comp.mail.elm           the ELM mail system.
             comp.mail.mh            The Rand Message Handling system.
             comp.mail.mime          Multipurpose Internet Mail Extensions.
             comp.mail.misc          General discussions about computer mail.
             comp.mail.multi-media   Multimedia Mail.
             comp.mail.mush          The Mail User's Shell (MUSH).
             comp.mail.sendmail      the BSD sendmail agent.
             comp.mail.smail         the smail mail agent.
             comp.mail.uucp          Mail in the uucp environment.



  2.3.  Mailing Lists


  There are many sendmail, smail and qmail mailing lists.

  You can find addresses in /usr/doc/the_one_you_have_chosen.


  2.4.  Other documents from LDP


  There is plenty of excellent material provided in the other Linux
  HOWTO documents and from the Linux DOC project.

  In particular, you might want to take a look at the following:


  �  on your own computer in /usr/doc/ :-)

  �  the Linux Networking Administrators' Guide

  �  the Mail Users HOWTO

  �  the Serial Communications HOWTO

  �  the Ethernet HOWTO

  �  the UUCP HOWTO if you're fed via UUCP


  2.5.  Books


  The following is a non-inclusive set of books that will help:


  �  "Managing UUCP and USENET" from O'Reilly and Associates is in my
     opinion the best book out there for figuring out the programs and
     protocols involved in being a USENET site.

  �  "Unix Communications" from The Waite Group contains a nice
     description of all the pieces (and more) and how they fit together.

  �  "Sendmail" from O'Reilly and Associates looks to be the definitive
     reference on sendmail-v8 and sendmail+IDA.  It's a "must have" for
     anybody hoping to make sense out of sendmail without bleeding in
     the process.

  �  "The Internet Complete Reference" from Osborne is a fine reference
     book that explains the various services available on Internet and
     is a great source for information on news, mail and various other
     Internet resources.

  �  "The Linux Networking Administrators' Guide" from Olaf Kirch of the
     Linux Documentation Project is available on the net and is also
     published by (at least) O'Reilly and SSC.

     It makes a fine one-stop shop to learn about everything you ever
     imagined you'd need to know about Unix networking.



  3.  How Electronic Mail Works

  Now we'll explain the flow of information that typically takes place
  when two people to communicate by email.  Let us suppose that Alice,
  on her machine wonderland.com, wants to send mail to Bob, on his
  machine dobbs.com.  Both machines are connected to the Internet.

  It helps to know that an Internet mail message consists of two parts;
  mail headers and a mail body, separated by a blank line.  The mail
  headers contain the source and destination of the mail, a user-
  supplied subject line, the date it was sent, and various other kinds
  of useful information.  The body is the actual content of the message.
  Here's an example:


  From: "Alice" <alice@wonderland.com>
  Message-Id: <199711131704.MAA18447@wonderland.com>
  Subject: Have you seen my white rabbit?
  To: bob@dobbs.org (Bob)
  Date: Thu, 13 Nov 1997 12:04:05 -0500 (EST)
  Content-Type: text

  I'm most concerned.  I fear he may have fallen down a hole.
  --
                                                  >>alice>>



  The arrangement and meaning of Internet mail headers are defined by an
  Internet standard called RFC822 <ftp://ftp.isi.edu/in-
  notes/rfc822.txt>.


  3.1.  Mail between full-time Internet machines

  Here's a diagram of the whole process -- I'll explain all the stages
  and terminology below.



  ______________________________________________________________________
                     +---------+          +-------+
  +-------+  types   | sending |  calls   |sending|
  | Alice |--------->|   MUA   |--------->|  MTA  |::::>::::
  +-------+          |         |          |       |       ::   on the
                     +---------+          +-------+       ::   sending
                                                          ::   machine
  .......................................................................
                               SMTP                       ::
   ::::::::::::::::::::::::::::<::::::::::::::::::::::::::::
   ::
   ::   +---------+          +-----+                +-------+
   ::   |receiving|  calls   |     |  delivers to   | Bob's |
   ::::>|   MTA   |--------->| LDA |===============>|mailbox|  on the
        |         |          |     |                |       |  receiving
        +---------+          +-----+                +-------+  machine
                                                      |   |
                                                      |   |
                       +----------------<-------------+   |
                       |                                  |
                  +---------+         +-------+           |
                  |  Bob's  |         | Bob's |<----------+
                  | notifier|         |  MUA  |
                  +---------+         +-------+
                       |                  |
                       |      +-----+     |
                       +----->| Bob |<----+
                              +-----+
  ______________________________________________________________________



  To send mail, Alice will invoke a program called a mail user agent (or
  MUA for short).  The MUA is what users think of as `the mailer'; it
  helps her compose the message, usually by calling out to a text editor
  of her choice.  When she hits the MUA `send' button, her part of the
  process is done.  Later in this HOWTO we will survey popular MUAs.

  The MUA she uses immediately hands her message to a program called a
  mail transport agent (or MTA). Usually this program will be sendmail,
  though some alternative MTAs are gaining popularity and may appear in
  future Linux distributions.  Later in this HOWTO we will also survey
  MTAs.

  The MTA's job is to pass the mail to an MTA on Bob's machine.  It
  determines Bob's machine by analyzing the To header and seeing the
  dobbs.com on the right-hand side of Bob's address.  It uses that
  address to open an Internet connection to Bob's machine.  The
  mechanics of making that connection are a whole other topic; for this
  explanation, it's enough to know that that connection is a way for
  Alice's MTA to send text commands to Bob's machine and receive replies
  to those commands.

  The MTA's commands don't go to a shell.  Instead they go to a service
  port on Alice's machine.  A service port is a sort of rendezvous, a
  known place where Internet service programs listen for incoming
  requests.  Service ports are numbered, and Alice's MTA knows that it
  needs to talk to port 25 on Bob's machine to pass mail.

  On port 25, Bob's machine has its own MTA listening for commands
  (probably another copy of sendmail).  Alice's MTA will go through a
  dialogue with Bob's using Simple Mail Transfer Protocol (or SMTP).
  Here is what an SMTP dialogue looks like.  Lines sent by Alice's
  machine are shown with S:, responses from Bob's machine are shown with
  R:.

        S: MAIL FROM:<alice@wonderland.com>
        R: 250 OK
        S: RCPT TO:<bob@dobbs.com>
        R: 250 OK
        S: DATA
        R: 354 Start mail input; end with <CRLF>.<CRLF>
        S: From: "Alice" <alice@wonderland.com>
        S: Message-Id: <199711131704.MAA18447@wonderland.com>
        S: Subject: Have you seen my white rabbit?
        S: To: bob@dobbs.org (Bob)
        S: Date: Thu, 13 Nov 1997 12:04:05 -0500 (EST)
        S: Content-Type: text
        S:
        S: I'm most concerned.  I fear he may have fallen down a hole.
        S: --
        S:                                                 >>alice>>
        S: .
        R: 250 OK



  Usually an SMTP command is a single text line and so is its response.
  The DATA command is an exception; after seeing that, the SMTP listener
  accepts message lines until it sees a period on a line by itself.
  (SMTP is defined by the Internet standard RFC821
  <ftp://ftp.isi.edu/in-notes/rfc821.txt>.)

  Now Bob's MTA has Alice's message.  It will add a header to the
  message that looks something like this:


  Received: (from alice@wonderland.com)
          by mail.dobbs.com (8.8.5/8.8.5) id MAA18447
          for bob@dobbs.com; Thu, 13 Nov 1997 12:04:05 -0500



  This is for tracking purposes in case of mail errors (sometimes a
  message has to be relayed through more than one machine and will have
  several of these).  Bob's MTA will pass the modified message to a
  local delivery agent or LDA.  On Linux systems the LDA is usually a
  program called procmail, though others exist.

  The LDA's job is to append the message to Bob's mailbox.  It's
  separate from the MTA so that both programs can be simpler, and so the
  MTA can concentrate on doing Internet things without worrying about
  local details like where the user mailboxes live.

  Bob's mailbox will normally be a file called /usr/spool/mail/bob or
  /var/mail/bob.  When he reads mail, he runs his own MUA (mail user
  agent) to look at and edit that file.


  3.2.  Notifiers

  There's yet another kind of program that is important in the mail
  chain, though it does not itself read or transmit mail.  It's a mail
  notifier, a program that watches your email in-box for activity and
  signals you when new mail is present.

  The original notifier was a pair of Unix programs called biff(1) and
  comsat(8). The biff program is a front end that enables you to turn on
  the comsat service.  When this service is on, the header of new mail
  will be dumped to your terminal as it arrived.  This facility was
  designed for people using line-oriented programs on CRTs; it's not
  really a good idea in today's environment.
  Most Unix shells have built-in mailcheck facilities that allow them to
  function as notifiers in a rather less intrusive way (by emitting a
  message just before the prompt when new mail is detected).  Typically
  you can enable this by setting environment variables documented on the
  shell's manual page.  For shells in the sh/ksh/bash family, see the
  MAIL and MAILPATH variables

  Systems supporting X come with one of several little desktop gadgets
  that check for new mail periodically and give you both visible and
  audible indication of new mail.  The oldest and most widely used of
  these is called xbiff; if your Linux has a preconfigured X desktop
  setup, xbiff is probably on it.  See the xbiff(1) manual page for
  details.


  3.3.  Mail to part-time Internet machines

  If you were reading carefully, you may have noticed that the
  information flow we described above depends on Alice's machine being
  able to talk to Bob's machine immediately.  What happens if Bob's
  machine is down, or is up but not connected to the Internet?

  If Alice's MTA can't reach Bob's immediately, it will stash Alice's
  message in a mail queue on wonderland.com.  It will then retry sending
  the mail at intervals until an expiration time is reached, at which
  point a bounce message notifying Alice of the failure will be sent
  back to her.  In the default configuration of the most popular MTA
  (sendmail), the retry interval is 15 minutes and the expiration time
  is 4 days.


  3.4.  Remote mail and remote-mail protocols

  Many Linux users nowadays are connected to the Internet via ISPs
  (Internet Service Providers) and don't have their own Internet
  domains.  Instead they have accounts on an ISP machine.  Their mail
  gets delivered to a mailbox on that ISP machine.  But typically these
  users want to read and reply to their mail using their own machines,
  which connect to the ISP intermittently using SLIP or PPP.  Linux
  supports remote mail protocols to support this.

  Note how this is different from the scenario we discussed in the last
  section.  Mail sitting in a queue awaiting retransmission is not the
  same as mail dispatched to a server mailbox; mail in a queue is not
  considered to have been delivered and is subject to expiration, but
  mail delivered to an ISP server mailbox is considered `delivered' and
  can sit there indefinitely.

  A remote-mail protocol allows mail on a server to be pulled across a
  network link by a client program (this is the opposite of normal
  delivery in which an MTA pushes mail to a receiving MTA).  There are
  two remote-mail protocols in common use; POP3 (defined by the Internet
  standard RFC1939 <ftp://ftp.isi.edu/in-notes/rfc1939.txt>) and IMAP
  (defined by the Internet standard RFC2060 <ftp://ftp.isi.edu/in-
  notes/rfc2060.txt>).  Effectively all ISPs support POP3; a growing
  number support IMAP (which is more powerful).

  Here is what an example POP3 session looks like:



        S: <client connects to service port 110>
        R:    +OK POP3 server ready <1896.697170952@mailgate.dobbs.org>
        S:    USER bob
        R:    +OK bob
        S:    PASS redqueen
        R:    +OK bob's maildrop has 2 messages (320 octets)
        S:    STAT
        R:    +OK 2 320
        S:    LIST
        R:    +OK 2 messages (320 octets)
        R:    1 120
        R:    2 200
        R:    .
        S:    RETR 1
        R:    +OK 120 octets
        R:    <the POP3 server sends message 1>
        R:    .
        S:    DELE 1
        R:    +OK message 1 deleted
        S:    RETR 2
        R:    +OK 200 octets
        R:    <the POP3 server sends message 2>
        R:    .
        S:    DELE 2
        R:    +OK message 2 deleted
        S:    QUIT
        R:    +OK dewey POP3 server signing off (maildrop empty)
        S:  <client hangs up>



  An IMAP session uses different commands and responses, but is
  logically very similar.


  To take advantage of POP3 or IMAP, you need a remote mail client
  program to pull your mail.  Some mail user agents have client
  capabilities built in (which one supports which is noted below), and
  the Netscape browser's mail facility supports both POP and IMAP
  natively.

  The main drawback of POP client facilities built into MUAs is that you
  have to explicitly tell your mailer to poll the server; you don't get
  notified by xbiff(1) or equivalent, as you would for mail that is
  either local or delivered by a conventional SMTP `push' connection.
  Also, of course, not all MUAs can do POP/IMAP, so you may find
  yourself compromising on other features.

  Your Linux probably comes with a program called fetchmail
  <http://www.tuxedo.org/~esr/fetchmail> that is designed specifically
  to talk to remote-mail servers, fetch mail, and feed it into your
  normal mail delivery path by speaking SMTP to your listener.

  Unless you need to keep your mail on the server (for example, because
  you move around between client machines a lot) fetchmail is probably a
  better solution than whatever POP/IMAP features your user agent has.
  Fetchmail can be told to run in background and poll your server
  periodically, so your xbiff(1) or other mail-notifier program will
  work as it would for SMTP mail.  Also, fetchmail is rather more
  tolerant of various idiosyncracies and nonstandard server quirks than
  the clients in MUAs, and has better error recovery.

  Here's a diagram showing how both cases (with and without fetchmail)
  work:


  ______________________________________________________________________
                     +---------+          +-------+
  +-------+  types   | sending |  calls   |sending|
  | Alice |--------->|   MUA   |--------->|  MTA  |::::>::::
  +-------+          |         |          |       |       ::
                     +---------+          +-------+       ::   on the
                                                          ::   sending
                               SMTP                       ::   machine
   ::::::::::::::::::::::::::::<::::::::::::::::::::::::::::
   ::
  .::.......................................................................
   ::
   ::   +---------+          +-----+             +-------+
   ::   |receiving|  calls   |     |  delivers   | Bob's |
   ::::>|   MTA   |--------->| LDA |============>|server |::::>::::
        |         |          |     |    to       |mailbox|       ::  on the
        +---------+          +-----+             +-------+       ::   mail
                                                                 ::  server
                            POP or IMAP                          ::
   ::::::::::::::::::::::::::::<:::::::::::::::::::::::::::::::::::
   ::
  .::........................................................................
   ::
   ::                  +-----------+
   ::                  |           |
   :::::::>::::::::::::| fetchmail |::::::::               on the
   ::                  |           |      ::              receiving
   ::                  +-----------+      ::               machine,
   ::                                     ::             with fetchmail
   ::   ::::::::::::::::<:::::::::::::::::::
   ::   ::
   ::   ::   +---------+          +-----+                +-------+
   ::   ::   |receiving|  calls   |     |  delivers to   | Bob's |
   ::   ::::>|   MTA   |--------->| LDA |===============>|mailbox|
   ::        |         |          |     |                |       |
   ::        +---------+          +-----+                +-------+
   ::                                                      |   |
   ::                                                      |   |
   ::                       +----------------<-------------+   |
   ::                       |                                  |
   ::                  +---------+         +-------+           |
   ::                  |  Bob's  |         | Bob's |<----------+
   ::                  | notifier|         |  MUA  |
   ::                  +---------+         +-------+
   ::                       |                  |
  .::........................................................................
   ::                   .   |                  |
   ::     without       .   |                  |
   ::    fetchmail      .   |                  |
   ::                   .   |      +-----+     |
   ::   +----------+    .   +----->|     |<----+
   ::   |  Bob's   |    .          | Bob |
   :::::| POP/IMAP |----.--------->|     |
        |   MUA    |    .          +-----+
        +----------+    .
  ______________________________________________________________________



  3.5.  Mailbox formats

  When incoming mail gets appended to a mailbox, it's up to the MTA to
  provide some kind of delimiters that tell where one message stops and
  the next begins.
  Under Unix, the convention almost all mailers use is that each line
  beginning with ``From '' (the space is significant) begins a new
  message.  If ``From '' occurs at the beginning of a line in text, a
  Unix MTA will generally prefix it with a greater-than sign, so it
  looks like ``>From ''.  RFC822 headers follow this From line (which
  usually continues with the sender name and receipt date).

  This convention originated with Unix Version 7, so this kind of
  mailbox is referred to as a ``V7 mailbox''; it is also sometimes
  called ``mbox format''.  Unless otherwise noted, all programs
  mentioned in this HOWTO expect this format.  It is not, however, quite
  universal, and tools expecting and generating different formats can
  confuse each other badly.

  The four other formats to know about (and beware of!) are BABYL, MMDF,
  MH, and qmail maildir.  Of these, MMDF is the simplest; it uses a
  delimiter line consisting four control-As (ASCII 001) characters
  followed by CR-LF.  MMDF was an early and rather crude Internet mail
  transport; a descendant is still in use on SCO systems.

  BABYL is another survival, from an early mail system at MIT.  It is
  still used by Emacs's mail-reader mode.

  MH and qmail maildir are `mailbox' formats which actually burst each
  mailbox into a directory of files, one per message.  Running grep on
  such a `mailbox' will get you nowhere, since all grep will see are the
  directory bits.

  Microsoft Outlook Express .mbx mailboxes can be converted to RFC822
  format with mbx2mbox app.


  4.  Requirements



  4.1.  Hardware


  There are no specific hardware requirements for mail under Linux.

  You'll need some sort of 'transport' software to connect to remote
  systems, which means either TCP/IP or uucp.

  This could mean that you need a modem or ethernet card, depending on
  your setup.  In most cases, you'll want the fastest modem you can
  afford, i.e. V90 57 600 bps currently.  In general, you want to have a
  16550 UART on your serial board or built into your modem to handle
  speeds of above 9600 baud.

  If you don't know what that last sentence means, please consult the
  comp.dcom.modems group or the various fine modem and serial
  communications FAQs and periodic postings on USENET.


  5.  Choosing a Mail Transport Agent

  Mail transport agents are the software that transfers mail from your
  local system to remote systems.  It is very seldom necessary to mess
  with or replace your MTA on a modern Linux, and you're better off not
  fixing what isn't broken.  Nevertheless, here's a survey to get you
  started on understanding what the tradeoffs are if you decide you need
  more security or performance than your system's default can offer.

  (There are other Unix MTAs besides these, but you are quite unlikely
  to encounter them on a Linux box.)
  Each has its own unique features, but the best compromise is qmail. It
  features high security (even if vmail is more secure), high speed
  (even if smail is faster for local uses) and ease of configuration.
  Of course, feel free to choose any mail software. The information
  provided here is intended to help you choose well.

  Sendmail can be nice for many sites with complicated options, but I
  think its configuration is too hard for beginners while it is not very
  secure or very fast, so there is only a really outdated sendmail
  section in this HOWTO.

  If you know what you're doing, choose sendmail (and you shouldn't be
  reading this HOWTO!); otherwise I generally recommend qmail.

  Detailed descriptions of these programs follow.


  5.1.  sendmail

  BSD sendmail is the grandaddy of Internet MTAs.  It has outlasted a
  few would-be successors.  Most Linux distributions now use it and have
  it preinstalled.


  Sendmail has a long-standing reputation for being an administrator's
  nightmare -- hard to understand, tricky to configure, rife with
  security holes.  As Internet technology and standards have stabilized,
  however, many of the sendmail options and configurable rules that gave
  rise to this reputation have ceased to require per-site tweaking (the
  effective demise of non-TCP/IP network layers like UUCP has helped a
  lot).  Also, recent sendmail versions have an improved configuration
  system that insulates you from the legendary hideousness of the
  sendmail.cf configuration file.  Most importantly, sendmail now
  normally comes preconfigured, and you should never need to touch it
  unless you have unusual requirements (such as needing to route mail
  over a non-TCP/IP network).


  There is a sendmail home page at  <http://www.sendmail.org>.  It
  includes references to extensive documentation of sendmail, should you
  actually need to wrestle with custom-configuring it.


  Other MTAs, if called as `sendmail', may mimic the semantics of
  sendmail's command-line options.  This is convenient for mail user
  agents, which often assume they are talking to sendmail.



  5.2.  smail v3.2

  Smail was the first serious attempt to replace sendmail.  It has a
  simpler and much more comprehensible configuration system than
  sendmail's, and it's fairly secure.  Some Linux distributions
  preinstall it rather than sendmail.


  At one time smail's excellent support for mixed TCP/IP and UUCP sites
  was a major selling point for it, but as UUCP has declined, so has
  smail.  Also, smail is less efficient than sendmail on high-volume
  connections.


  As with sendmail, it is unlikely that you will need to tweak a
  preinstalled smail configuration.

  (Very occasionally you might run across references to an `smail 2.5'.
  This program has been obsolete for a long time.  Don't bother with
  it.)


  5.3.  qmail

  The qmail program is a sendmail-compatible MTA designed specifically
  for high security.  The author has a standing reward of $500 for
  publication of the first verifiable security hole; this reward has
  gone unclaimed since March 1997.

  The qmail home page is at  < http://pobox.com/~djb/qmail.html>.


  5.4.  exim

  The exim program is similar to smail3, but with more features.  It
  advertises particular strengths in spam-blocking and support of
  several virtual hosts (virtual DNS domains) on the same host.

  The exim home page is at  < http://www.exim.org/>.

  I tried it on my own computer, it looks like a nice merge between
  smail configuration system and qmail security, moreover it has the
  advantage of being GPL.

  A section explaining how to replace your current MTA by exim will be
  added soon.


  6.  Installing Transport Software



  6.1.  Qmail v1.03


  Secured, fast and easy to use, this is my preferred MTA (mail
  transport agent).

  Currently, no distribution comes with qmail preinstalled.  We will
  focus on compiling and installing qmail, since this is the only tricky
  part: configuration is really straightforward.


  6.1.1.  Getting qmail


  Go to www.qmail.org to download the latest version.


  6.1.2.  Uncompressing sources


  Then decompress it by running:


       mv qmail.tar.gz /usr/local/src
       cd /usr/local/src ; tar -zxvf qmail.tar.gz



  If you find a bz2 version (new and better compression format), just
  replace tar with:
       bunzip2 qmail.tar.bz2
       tar -xvf qmail.tar



  6.1.3.  Preparing for compilation


  Now enter the qmail directory to examine the configuration defaults:


       cd qmail; more conf-*



  You shouldn't need to change any defaults, but you could (for example)
  specify an alternate installation directory or better compilation
  flags.

  Now run:


       mkdir /var/qmail



  to create target dir.

  If you haven't installed a Debian distribution, you'll need to add
  several user IDs for qmail's use: qmail's high security depends on
  that.

  The fact that qmail is divided into modules running each under their
  own UID makes it much harder for an intruder to break your whole mail
  system or gain root access by abusing it.

  So run:


          # groupadd nofiles
          # useradd -g nofiles -d /var/qmail/alias alias
          # useradd -g nofiles -d /var/qmail qmaild
          # useradd -g nofiles -d /var/qmail qmaill
          # useradd -g nofiles -d /var/qmail qmailp
          # groupadd qmail
          # useradd -g qmail -d /var/qmail qmailq
          # useradd -g qmail -d /var/qmail qmailr
          # useradd -g qmail -d /var/qmail qmails



  or hand-edit /etc/passwd and /etc/group to add these users by
  yourself.

  Evan E. reported he had to use "-g groupid" parameter for a vanilla
  groupadd (Caldera 1.2), else groupadd reported this error : "A group
  with that name already exists."

  For example you can respectively add:


               qmail:*:2107:
               nofiles:*:2108:



  &



               alias:*:7790:2108::/var/qmail/alias:/bin/true
               qmaild:*:7791:2108::/var/qmail:/bin/true
               qmaill:*:7792:2108::/var/qmail:/bin/true
               qmailp:*:7793:2108::/var/qmail:/bin/true
               qmailq:*:7794:2107::/var/qmail:/bin/true
               qmailr:*:7795:2107::/var/qmail:/bin/true
               qmails:*:7796:2107::/var/qmail:/bin/true



  Now you can run


       make setup check



  to check your configuration, then :


       ./config



  to configure qmail.

  Attention, your server has to be resolvable by DNS or ./config will
  get confused.

  If you don't have DNS access, you can give your server name directly
  via :


       ./config-fast foo.bar.com



  Now you must install some aliases, since /etc/alias is not used by
  qmail unless you compile and install an optional package.

  Here's my setup :



  File : ".qmail-MAILER-DAEMON"
  &postmaster
  File : ".qmail-bin"
  &root
  File : ".qmail-daemon"
  &root
  File : ".qmail-decode"
  &root
  File : ".qmail-dumper"
  &root
  File : ".qmail-games"
  &root
  File : ".qmail-ingres"
  &root
  File : ".qmail-mailer-daemon"
  &postmaster
  File : ".qmail-manager"
  &root
  File : ".qmail-news"
  &root
  File : ".qmail-nobody"
  &root
  File : ".qmail-operator"
  &root
  File : ".qmail-postmaster"
  &root
  File : ".qmail-root"
  &guylhem
  File : ".qmail-system"
  &root
  File : ".qmail-toor"
  &root
  File : ".qmail-uucp"
  &root
  File : ".qmail-uucp-default"
  |preline -dr /usr/bin/uux - -r -gC -a"${SENDER:-MAILER-DAEMON}" lm!rmail "($DEFAULT@$HOST)"



  You need to create each of these file in ~alias, replacing &guylhem in
  .qmail-root by your own login to get root mail.

  ATTENTION UUCP USERS !

  DO NOT TRUST THE QMAIL FAQ FOR UUCP, USE MY .qmail-uucp-default
  INSTEAD!  ELSE YOU WILL NOT BE ABLE TO SEND ANY MAIL BY YOUR UUCP
  CONNEXION!

  Now you'll need to decide in which format your users will get their
  mail.

  Here's my suggestion :

  �  For NFS mounted home dirs, use MAILDIR format with a patch for
     local mail readers (patchs are available on www.qmail.org)

  �  If no patch is available, prefer MAILFILE format : any mail reader
     can read a file containing mail, people will only need to create an
     alias (for bash) or a setenv (for csh) for their mail reader

  �  Avoid /var/spool/mail/$USER format, too insecure

  To fix the default format, read each file in /var/qmail/boot then copy
  the one you best like to /var/qmail/rc.

  home or proc are safe choices, but prefer home for security reasons.


  6.1.4.  Configuring qmail


  In /var/qmail/control, edit:


  6.1.4.1.  defaultdomain, me, plusdomain



  �  me is you local FQDN (full qualified domain name), for example on
     my machine it is barberouge.linux.lmm.com

  �  defaultdomain will be added to any host name without dots,
     including defaulthost, for example you can set it to localnetwork
     so any mail sent to joe@hisbox will be completed to be sent to
     joe@hisbox.localnetwork instead

  �  plusdomain is the exception: it is added to any host name that ends
     with a plus sign, including defaulthost (set in me) if it ends with
     a plus sign.

  These 3 examples show you the power and ease of configuration of
  qmail!


  6.1.4.2.  locals, rcpthosts


  If you want to support virtual domain names, just put additional names
  in these files. Any mail you receive for these names will be handled
  locally.

  The difference between locals and rcpthosts is the latter isn't
  considered as a local alias, which is useful if you receive mail from
  some free email address like yahoo.com or lemel.fr while you also send
  mail to other users of these non local services, i.e. you don't want
  to handle locally mail send to someone@yahoo.com!


  6.1.4.3.  virtualdomains


  There can you specify default outgoing mode, for example :


       #:alias-uucp



  if you don't want to send outgoing mail by uucp but by smtp (default)
  or


       :alias-ucp



  if you send your outgoing mail by uucp.


  6.1.5.  Testing qmail


  Now it is configured, try:


       sh -cf '/var/qmail/rc &'



  to launch qmail (it won't interfere with your local MTA), then:



       echo to: mylogin | /var/qmail/bin/qmail-inject



  You should receive this mail in the format you've chosen in
  /var/qmail/boot/.


  6.1.6.  Removing your other MTA


  If this test was successful, just kill your previous MTA:

  killall -STOP daemon_name ; if any children are running, you should
  killall -CONT their_name, wait, killall -STOP again, and repeat ad
  nauseam.

  If there aren't any children, killall -TERM and then killall -CONT.

  Remove it (how you can do this depends on the distribution you
  installed, for example rpm -e --nodeps on RedHat, Caldera and Suse, or
  dpkg -r --force-depends on Debian) then run:


       # ln -s /var/qmail/bin/sendmail /usr/lib/sendmail
       # ln -s /var/qmail/bin/sendmail /usr/sbin/sendmail



  Now set up qmail-smtpd in /etc/inetd.conf (all on one line):


       smtp stream tcp nowait qmaild /var/qmail/bin/tcp-env tcp-env /var/qmail/bin/qmail-smtpd



  If you are using a old non-SYSV-init distribution like redhat, just
  add to your boot scripts:


       sh -cf '/var/qmail/rc &'



  Usually this should be /etc/rc.local but your mileage may vary.


  For actual SYSV-init compliant distributions (RedHat, Caldera, Suse,
  Debian), add this script to /etc/init.d/ or /etc/rc.d/init.d/ :

  DEBIAN version:



       #!/bin/sh

       test -x /var/qmail/rc || exit 0

       case "$1" in
         start)
            echo -n "Starting mta: "
            sh -cf '/var/qmail/rc &'
            echo "qmail."
            ;;
         stop)
            echo -n "Stopping mta: "
            killall qmail-lspawn
            echo "qmail."
            ;;
         restart)
            echo -n "Restarting mta: "
            killall -HUP qmail-lspawn
            killall -ALRM qmail-lspawn
            echo "qmail."
            ;;
         *)
            echo "Usage: /etc/init.d/qmail {start|stop|restart}"
            exit 1
       esac

       exit 0



  REDHAT version:



  #!/bin/sh
  #
  # qmail      This shell script takes care of starting and stopping qmail.
  #
  # description: qmail is a Mail Transport Agent, which is the program \
  #              that moves mail from one machine to another.
  # processname: qmail
  # config: /var/qmail/control/

  # Source function library.
  . /etc/rc.d/init.d/functions

  # Source networking configuration.
  . /etc/sysconfig/network

  export PATH=$PATH:/var/qmail/bin

  # Check that networking is up.
  [ ${NETWORKING} = "no" ] && exit 0

  [ -f /usr/sbin/sendmail ] || exit 0

  # See how we were called.
  case "$1" in
    start)
          # Start daemons.
          echo -n "Starting qmail: "
          qmail-start '|preline procmail' splogger qmail &
          touch /var/lock/subsys/qmail
          echo
          ;;
    stop)
          # Stop daemons.
          echo -n "Shutting down qmail: "
          killproc qmail-lspawn
          echo
          rm -f /var/lock/subsys/qmail
          ;;
    restart)
          $0 stop
          $0 start
          ;;
    status)
          status qmail
          ;;
    *)
          echo "Usage: qmail {start|stop|restart|status}"
          exit 1
  esac

  exit 0



  And make symlinks to each /etc/rc.d/rcN.d/, for example:


       ln -sf /etc/init.d/qmail /etc/rc1.d/K19qmail



  If the first letter is K, you will kill qmail on this runlevel (1 for
  single mode or 6 for boot), but if the first letter is S, you will
  start qmail on this runlevel (each others runlevel).
  �  How to decide whether you should put a K or a S?  Do what the
     majority of d�mons in this runlevel do!

  �  What number should you put after K or S?  The number next to your
     network daemon.

     That means the MTA will be started and stopped respectively after
     and before the network daemon.

     Without this, your network will be unreachable while the MTA would
     expect it to work.

  RedHat, Caldera and Suse will use /etc/rc.d/ instead of plain /etc/
  for Debian distribution, i.e. /etc/rc.d/rc1.d or /etc/rc.d/init.d for
  example.


  6.1.7.  That's all, folks!


  No need to reboot (remember, you're using linux, not some other cheap
  OS!) for the modifications to take effect, just run:



       killall inetd
       init 1



  To go to single user mode, then:


       init 2



  to go back to your default runlevel (indicated in /etc/inittab with
  initdefault label).

  You could also hand-start qmail script but "init" method will show you
  if qmail script is well positioned, i.e. launched after network
  scripts but before any program which depends on email to warn you
  (like inn).


  6.2.  Smail v3.1


  Smail3.1 seems to be a de-facto standard transport agent for uucp-only
  sites and for some smtp sites. It's easy to configure, it compiles
  without patching from the sources and it's fairly secure.


  6.2.1.  Configuring smail


  Install the smail binary from your distribution (I recommend you
  choose this) or get the smail sources and build smail. If you're
  building smail from sources, you need to have the following in your
  os/linux file so that 'sed' gives you shell scripts that work
  properly.


  CASE_NO_NEWLINES=true



  Once it's installed, config. files will certainly go in /etc/smail
  (but your mileage may vary if you use old distributions); let's start
  editing them!


  6.2.1.1.  "config" file



       # From
       smart_path=polux
       smart_transport=uux

       # To
       hostname=barberouge
       domains=linux.lmm.com

       visible_name=barberouge.linux.lmm.com
       uucp_name=barberouge.linux.lmm.com

       # max_message_size=512k
       # auth_domains=foo.bar
       # more_hostnames=barberouge.polux.freenix.fr



  Well, first, who is feeding you? I'm fed by "polux" via uucp (i.e.
  uux transport); naturally you need to change this file according to
  your own situation. For example, you could by fed by
  "bargw.bar.foobar.com" via "smtp", in that case you don't need a
  transport file and can define "-transport_file " to indicate you don't
  need one.

  You can also use "postmaster_address = yourname", hide the network
  topology in outgoing addresses (if you're a gateway) using
  "visible_name", set which aliases address can also be used for the
  email you receive, using "more_hostnames".

  See smail documentation for more details or the examples in
  /usr/doc/smail/examples to see if any match your situation.


  6.2.1.2.  "directors" file



  # aliasinclude - expand ":include:filename" addresses produced by alias files
  # This entry and the next one are pretty much boiler-plate.  Reasons
  # for making significant changes are few.  The sole purpose of these
  # is to match and expand addresses of the form:
  #       :include:pathname
  # which may occur in alias files or mailing-list/forward files
  # (produced by any director with a driver of forwardfile).
  aliasinclude:
          driver = aliasinclude,          # use this special-case driver
          nobody;                         # associate nobody user with addresses
                                          #  when mild permission violations
                                          #  are encountered
          copysecure,                     # get permissions from alias director
          copyowners,                     # get owners from alias director



  # forwardinclude - expand ":include:filename" addrs produced by forward files
  forwardinclude:
          driver = forwardinclude,        # use this special-case driver
          nobody;
          copysecure,                     # get perms from forwarding director
          copyowners,                     # get owners from forwarding director


  # aliases - search for alias expansions stored in a database
  # This is the standard aliases file.  It is used for generic things,
  # like mapping root, postmaster, MAILER-DAEMON and uucp to site
  # admins, creating some small system alias expansions, and such.  In
  # this site configuration, the aliases file is used mostly for
  # machine-specific aliasing/forwarding information.  Global forwarding
  # information should be put in the "forward" database.
  aliases:
          driver=aliasfile,               # general-purpose aliasing director
          -nobody,                        # all addresses are associated
                                          # with nobody by default, so setting
                                          # this is not useful.
          sender_okay,                    # don't remove sender from expansions
          owner=owner-$user;              # problems go to an owner address
          file=/etc/aliases,
          modemask=002,                   # should not be globally writable
          optional,                       # ignore if file does not exist
          proto=lsearch,                  # unsorted ASCII file


  # forward - search for expansions stored in a forwarding database
  # This is the subdomain-wide user forwarding database.  Entries are
  # maintained here for current or past users, to forward their mail to
  # their preferred mail-reading machine.  The forward database is
  # shipped around the TCP/IP network as changes are made, to keep the
  # network consistent.
  #forward:
  #       driver = aliasfile,             # general-purpose aliasing director
  #       -nobody,                        # all addresses are associated
  #                                       # with nobody by default, so setting
  #                                       # this is not useful.
  #       owner = real-$user;             # problems go to an owner address
  #
  #       file = /etc/forward,
  #       modemask = 002,
  #       proto = dbm,                    # use dbm(3X) library for access


  # dotforward - expand .forward files in user home directories
  # For users that have an entry in the "forward" database, a ".forward"
  # file is only used if it is on the "home" machine, as identified in
  # the forward database.  If used, it is treated as a list of addresses
  # to which mail should be delivered, rather than (or in addition to)
  # the user identified in the local address.
  dotforward:
          driver = forwardfile,           # general-purpose forwarding director
          owner = postmaster, nobody, sender_okay;

          file = ~/.forward,              # .forward file in home directories
          checkowner,                     # the user can own this file
          owners = root,                  # or root can own the file
          modemask = 002,                 # it should not be globally writable
          caution = daemon:root,          # don't run things as root or daemon
          # be extra careful of remotely accessible home directories
          unsecure = "~uucp:/tmp:/usr/tmp:/var/tmp"


  # forwardto - expand a "Forward to " in user mailbox files
  # This emulates the V6/V7/System-V forwarding mechanism which uses a
  # line of forward addresses stored at the beginning of user mailbox files
  # prefixed with the string "Forward to "
  forwardto:
          driver = forwardfile,
          owner = postmaster, nobody, sender_okay;

          file = /var/spool/mail/${lc:user},      # point at user mailbox files
          forwardto,                      # enable "Forward to " function
          checkowner,                     # the user can own this file
          owners = root,                  # or root can own the file
          modemask = 0002,                # under System V, group mail can write
          caution = daemon:root           # don't run things as root or daemon


  # user - match users on the local host with delivery to their mailboxes
  user:   driver = user;                  # driver to match usernames
          transport = local               # local transport goes to mailboxes


  # real_user - match usernames when prefixed with the string "real-"
  # This is useful for allowing an address which explicitly delivers to a
  # user's mailbox file.  For example, errors in a .forward file expansion
  # could be delivered here, or forwarding loops between multiple machines
  # can be resolved by using a real-username address.  Also, users that
  # wish to use mail as a means of transferring data to a machine that
  # is not their "home" machine can mail to real-login-name@remote.host.
  real_user:
          driver = user;
          transport = local,
          prefix = "real-"            # for example, match real-root


  # lists - expand mailing lists stored in a list directory
  # mailing lists can be created simply by creating a file in the
  # /etc/smail/lists directory.
  lists:  driver = forwardfile,
          caution,                        # flag all addresses with caution
          nobody,                         # and then associate the nobody user
          owner = owner-$user;            # system V sites may wish to use
                                          # o-$user, as owner-$user may be
                                          # too long for a 14-char filename.
          file = lists/${lc:user}         # lists is under $smail_lib_dir


  # owners - expand mailing lists stored in a list owner directory
  # mailing lists owner lists can be created simply by creating a file
  # in the /etc/smail/lists/owner directory.  Mailing list owners
  # are sent locally generated errors dealing with a mailing list of the
  # same name.  To create an owner list for a mailing list, create a
  # file with the name of the list in /etc/smail/lists/owner.  This
  # will create a list address of owner-listname, as is used by the
  # "lists" director above.
  owners: driver = forwardfile,
          caution,                        # flag all addresses with caution
          nobody,                         # and then associate the nobody user
          owner = postmaster;             # system V sites may wish to use
                                          # o-$user, as owner-$user may be
                                          # too long for a 14-char filename.
          prefix = "owner-",
          file = lists/owner/${lc:user}   # lists is under $smail_lib_dir


  # request - expand mailing lists stored in a list request directory
  # mailing lists request lists can be created simply by creating a file
  # in the /etc/smail/lists/request directory.  Request addresses
  # are typically used as a standard address for queries about a mailing
  # list.  For example, requests for additions or deletions to a list
  # will generally be sent to "list-request", which should be set up to
  # forward to the appropriate person or persons.
  request: driver = forwardfile,
          caution,                        # flag all addresses with caution
          nobody,                         # and then associate the nobody user
          owner = postmaster;             # system V sites may wish to use
                                          # o-$user, as owner-$user may be
                                          # too long for a 14-char filename.
          suffix = "-request",
          file = lists/request/${lc:user} # lists is under $smail_lib_dir



  You shouldn't need to change anything here, only mailing list options
  if you intend to run some using smail, or forwards options if, for
  example, you want to disable forwarding.


  6.2.1.3.  "fidopaths" file



       .f105.n324.z2.fidonet.org     f105.n324.z2.fidonet.org!%s
       .n324.z2.fidonet.org          f105.n324.z2.fidonet.org!%s
       .z2.fidonet.org                       f105.n324.z2.fidonet.org!%s
       .fidonet.org                  f105.n324.z2.fidonet.org!%s



  Create such a file only if you're using ifmail and FIDO.


  6.2.1.4.  "routers" file



  # forces - force certain paths
  # This database exists as a means of hardcoding the paths to various
  # machines or domains.  It is for use in creating temporary tweaks to
  # the other routing databases.  To change the database, edit the file
  # maps/force.path and type "make" in the maps/ subdirectory.
  forces:
          driver = pathalias,             # router to search paths file
          method = /etc/smail/maps/table; # transports are in this file
          file = forcepaths,              # file containing force path info
          proto = lsearch,                # use the sorted path file
          optional,
          reopen                          # close when not being used


  uucp_neighbors:
          driver=uuname,                  # use a program which returns neighbors
          transport=uux;
          cmd="/usr/bin/uuname -a",       # specifically, use the uuname program
  #        domain=uucp                    # strip ending ".uucp"


  # smart_host - a partially specified smarthost director
  # If the config file attribute smart_path is defined as a path from the
  # local host to a remote host, then hostnames not matched otherwise will
  # be sent off to the stated remote host.  The config file attribute
  # smart_transport can be used to specify a different transport.
  # If the smart_path attribute is not defined, this router is ignored.
  smart_host:
          driver = smarthost,             # special-case driver
          transport = uux                 # by default deliver over UUCP
  #       path=phreak


  # ifmail - to send mails to fidonet and vice versa
  ifmail:
          driver=pathalias,
          transport=ifmail;
          file=fidopaths,
          proto=lsearch



  You should only include ifmail chapter if you use ifmail for FIDO
  mails. Note you can also change transport mode from "uux" (ie UUCP)
  to, for example, "smtp" or even 'hardcode the paths to various
  machines or domains' in "/etc/smail/maps/table".

  This is useful if you want outgoing mail for your local network to be
  delivered immediately, since there's no need for it to be routed to
  your uucp connexion of your internet access.


  6.2.1.5.  "transports" file



  # local - deliver mail to local users
  # Tell smail to append directly to user mailbox files in the /var/spool/mail
  # directory.
  #local: driver = appendfile,            # append message to a file
  #       -return_path,                   # include a Return-Path: field
  #       local,                          # use local forms for delivery
  #       from,                           # supply a From_ envelope line
  #       unix_from_hack;                 # insert > before From in body
  #
  #       file = /var/spool/mail/${lc:user},      # use this location for Linux
  #                                               # Note, mail spool must be 1777
  #       file = ~/mailfile,              # use this location for better security
  #       group = mail,                   # group to own file for System V
  #       mode = 0660,                    # under System V, group mail can access
  #       suffix = "\n",                     # append an extra newline
  #       append_as_user,


  # This allows each user to have a ~/.procmailrc file to control filtering
  # of mail and saving mail from mail lists in separate mailboxes if they wish.
  local:  +inet,
          -uucp,
          driver = pipe,                  # append message to a file
          return_path,                    # include a Return-Path: field
          local,                          # use local forms for delivery
          from,                           # supply a From_ envelope line
          unix_from_hack;                 # insert > before From in body

          cmd = "/usr/bin/procmail",  # use procmail for local delivery
          parent_env,                     # environment info from parent addr
          pipe_as_user,                   # use user-id associated with address
          umask = 0022,                   # umask for child process
  #       -ignore_status,                 # exit status should be believed
  #       -ignore_write_errors,           # retry on broken pipes


  # pipe - deliver mail to shell commands
  # This is used implicitly when smail encounters addresses which begin with
  # a vertical bar character, such as "|/usr/lib/news/recnews talk.bizarre".
  # The vertical bar is removed from the address before being given to the
  # transport.
  #pipe:  driver = pipe,                  # pipe message to another program
  #       return_path, local, from, unix_from_hack;
  #
  #       cmd = "/bin/sh -c $user",   # send address to the Bourne Shell
  #       parent_env,                     # environment info from parent addr
  #       pipe_as_user,                   # use user-id associated with address
  #       umask = 0022,                   # umask for child process
  #       -log_output,                    # do not log stdout/stderr
  #       ignore_status,                  # exit status may be bogus, ignore it
  #       ignore_write_errors,            # ignore broken pipes


  # file - deliver mail to files
  # This is used implicitly when smail encounters addresses which begin with
  # a slash or squiggle character, such as "/usr/info/list_messages" or
  # perhaps "~/Mail/inbox".
  #file:  driver = appendfile,
  #       return_path, local, from, unix_from_hack;
  #
  #       file = $user,                   # file is taken from address
  #       append_as_user,                 # use user-id associated with address
  #       expand_user,                    # expand ~ and $ within address
  #       check_path,
  #       suffix = "\n",
  #       mode = 0644
  # uux - deliver to the rmail program on a remote UUCP site
  #
  # As many as five recipient addresses will be delivered to the remote
  # host in one UUCP transaction.
  uux:    driver = pipe,
          -uucp,
          inet,
  #       uucp,                           # use UUCP-style addressing forms
          from,                           # supply a From_ envelope line
          max_addrs = 5,                  # at most 5 addresses per invocation
          max_chars = 200;                # at most 200 chars of addresses
  # the -r flag prevents immediate delivery, parentheses around the
  # $user variable prevent special interpretation by uux.
          cmd = "/usr/bin/uux - -r -g$grade $host!rmail $((${strip:user})$)",
  #        cmd="/usr/bin/uux - $host!rmail $(($user)$)",
          ignore_write_errors,            # ignore broken pipes
          umask = 0022,
  #       pipe_as_sender,


  # uux_one_addr - deliver mail over UUCP to a remote host that can take
  #                one address at a time.
  # This is often necessary when delivering to a site running an unmodified
  # version of 4.1BSD.
  uux_one_addr:
          driver = pipe,
          uucp,                           # use UUCP-style addressing forms
          from;                           # supply a From_ envelope line
  # the -r flag prevents immediate delivery
          cmd = "/usr/bin/uux - -r -g$grade $host!rmail (${strip:user})",
          umask = 0022,
          pipe_as_sender


  queueonly:
          driver = pipe;                  # send the message to a pipe
          cmd = "/usr/lib/sendmail -Q -f $sender -bm $user",
                                          # use getmail for local delivery
          user=root,                      # execute getmail as "root"
          group=mail,                     # execute getmail as "mail"
          parent_env,                     # environment info from parent addr
          -pipe_as_user,                  # use user-id associated with address
          umask = 0007,                   # umask for child process

  # to deliver the message.  The smtp transport is included only if BSD
  # networking exists.
  # The uucp attribute can be specified for transfers within the UUCP
  # zone.  The inet attribute must be specified for transfers within the
  # Internet.
  # NOTE: This is hardly optimal, a backend should exist which can handle
  #       multiple messages per connection.
  # ALSO: It may be necessary to restrict max_addrs to 100, as this is the
  #       lower limit SMTP requires an implementation to handle for one
  #       message.
  smtp:   driver=tcpsmtp,
          inet,                           # if UUCP_ZONE is not defined
  #       uucp,                           # if UUCP_ZONE is defined
          -max_addrs, -max_chars;         # no limit on number of addresses

          short_timeout=5m,               # timeout for short operations
          long_timeout=2h,                # timeout for longer SMTP operations
          service=smtp,                   # connect to this service port
  # For internet use: uncomment the below 4 lines
         use_bind,                       # resolve MX and multiple A records
         defnames,                       # use standard domain searching
         defer_no_connect,               # try again if the nameserver is down
         local_mx_okay,                  # fail an MX to the local host


  ifmail:
          from,received,max_addrs=5,max_chars=200,
          driver=pipe;
          pipe_as_sender,
          cmd="/usr/local/bin/ifmail -x9 -r$host $((${strip:user})$)"



  You should include an ifmail chapter only if you use ifmail for FIDO
  mail. Apart from that, you shouldn't need to edit anything in this
  file which defines transport agents (like uux, smtp ...) you can use
  as parameters in other config. files.

  Note I commented out some parts, like "pipes" or "file", to enhance
  security.


  6.2.1.6.  "maps/" directory


  It contains map and table files:

  First, map file



       #N      foo.bar foo2.bar2
       #S      AT 486/RedHat Linux 1.2.13
       #O      organization
       #C      contact
       #E      administration (email)
       #T      phone
       #P      address
       #R
       #U      hosts connected via uucp
       #W      created/edited by
       #
       hname polux

       hname linux.eu.org

       hname = polux
       hname = polux.linux.eu.org



  Once again, edit this file to match you situation (I'm fed by
  polux.linux.eu.org).

  Now table file



       *       uux



  You can define different transports to different paths, for example
  "smtp" for the machines in your local network, "uux" (i.e. uucp) for
  the rest of the world or vice-versa (I'm using uucp for any outgoing
  mail, therefore I use "*"!).


  6.2.2.  Other good examples


  The previous files are the one I currently use for my site, you
  shouldn't encounter any problem using them as samples/basis for your
  own files.

  The following files are provided only as good examples to configure
  smail a different way.



  #ident "@(#) transports,v 1.2 1990/10/24 05:20:46 tron Exp"

  # See smail(5) for a complete description of the contents of this file.

  # local - deliver mail to local users
  #
  # Tell smail to append directly to user mailbox files in the /usr/mail
  # directory.
  local:  driver = appendfile,            # append message to a file
          return_path,                    # include a Return-Path: field
          local,                          # use local forms for delivery
          from,                           # supply a From_ envelope line
          unix_from_hack;                 # insert > before From in body

          file = /usr/mail/${lc:user},    # use this location for System V
          group = mail,                   # group to own file for System V
          mode = 0660,                    # under System V, group mail can access
          suffix = "\n",                     # append an extra newline
          append_as_user,

  # pipe - deliver mail to shell commands
  #
  # This is used implicitly when smail encounters addresses which begin with
  # a vertical bar character, such as "|/usr/lib/news/recnews talk.bizarre".
  # The vertical bar is removed from the address before being given to the
  # transport.
  pipe:   driver = pipe,                  # pipe message to another program
          return_path, local, from, unix_from_hack;

          cmd = "/bin/sh -c $user",   # send address to the Bourne Shell
          parent_env,                     # environment info from parent addr
          pipe_as_user,                   # use user-id associated with address
          umask = 0022,                   # umask for child process
          -log_output,                    # do not log stdout/stderr
          ignore_status,                  # exit status may be bogus, ignore it
          ignore_write_errors,            # ignore broken pipes

  # file - deliver mail to files
  #
  # This is used implicitly when smail encounters addresses which begin with a
  # slash or squiggle character, such as "/usr/info/list_messages" or perhaps
  # "~/Mail/inbox".
  file:   driver = appendfile,
          return_path, local, from, unix_from_hack;

          file = $user,                   # file is taken from address
          append_as_user,                 # use user-id associated with address
          expand_user,                    # expand ~ and $ within address
          suffix = "\n",
          mode = 0644

  # uux - deliver to the rmail program on a remote UUCP site
  #
  # As many as five recipient addresses will be delivered to the remote host in
  # one UUCP transaction.
  uux:    driver = pipe,
          uucp,                           # use UUCP-style addressing forms
          from,                           # supply a From_ envelope line
          max_addrs = 5,                  # at most 5 addresses per invocation
          max_chars = 200;                # at most 200 chars of addresses

          # the -r flag prevents immediate delivery, parentheses around the
          # $user variable prevent special interpretation by uux.
          cmd = "/usr/bin/uux - -r -g$grade $host!rmail $((${strip:user})$)",
          umask = 0022,
          pipe_as_sender
  # uux_one_addr - deliver mail over UUCP to a remote host that can take one
  # address at a time.
  #
  # This is often necessary when delivering to a site running an unmodified
  # version of 4.1BSD.
  uux_one_addr:
          driver = pipe,
          uucp,                           # use UUCP-style addressing forms
          from;                           # supply a From_ envelope line

          # the -r flag prevents immediate delivery
          cmd = "/usr/bin/uux - -r -g$grade $host!rmail (${strip:user})",
          umask = 0022, pipe_as_sender

  # demand - deliver to a remote rmail program, polling on demand
  demand: driver = pipe,
          uucp, from, max_addrs = 5, max_chars = 200;

          # with no -r flag, try to contact remote site immediately
          cmd = "/usr/bin/uux - -g$grade $host!rmail $(($user)$)",
          umask = 0022, pipe_as_sender

  # uusmtp - deliver to the rsmtp program on a remote UUCP site
  #
  # Deliver using a simple Batched SMTP protocol to the remote machine.
  # This allows much more arbitrary addresses to be used.  It also
  # removes the limit on recipient addresses per invocation of uux.
  uusmtp: driver = pipe,
          bsmtp,                          # send batched SMTP commands
          -max_addrs,                     # there is no limit on the number or
          -max_chars;                     #   total size of recipient addresses.

          # supply -r to prevent immediate delivery, the recipient addresses
          # are stored in the data sent to the standard input of rsmtp.
          cmd = "/usr/bin/uux - -r -g$grade $host!rsmtp",
          umask = 0022, pipe_as_sender

  # demand_uusmtp - deliver to a remote rsmtp program, polling on demand
  demand_uusmtp:
          driver = pipe,
          bsmtp, -max_addrs, -max_chars;

          # with no -r flag, try to contact remote site immediately
          cmd = "/usr/bin/uux - -g$grade $host!rsmtp",
          umask = 0022, pipe_as_sender

  # smtp - deliver using SMTP over TCP/IP
  #
  # Connect to a remote host using TCP/IP and initiate an SMTP conversation to
  # deliver the message.  The smtp transport is included only if BSD networking
  # exists.

  # NOTE: It may be necessary to restrict max_addrs to 100, as this is the
  #       lower limit SMTP requires an implementation to handle for one
  #       message.
  smtp:   driver = smtp,
          -max_addrs,
          -max_chars



  #ident "@(#) table,v 1.2 1990/10/24 05:20:31 tron Exp"

  # This file names the transports that are to be used in delivering
  # to specific hosts from bargw.

  #host           transport
  #--------       ---------
  curdsgw         demand_uusmtp   # deliver using batched SMTP
  oldbsd          uux_one_addr    # 4.1BSD sites cannot take more than one addr
  sun             demand          # call sun when their is mail to send
  *               uux             # for all others, poll at intervals



  6.2.3.  Restarting inetd


  To run smail as a smtp daemon, add one of the following to
  /etc/inetd.conf:

           smtp stream tcp nowait  root  /usr/bin/smtpd smtpd

  or:

           smtp stream tcp nowait  root  /usr/sbin/tcpd  /usr/sbin/in.smtpd



  Outgoing mail gets sent automatically, when using elm.


  6.2.4.  Smail with smtp


  Generally, ISPs use smtp, therefore you shouldn't have any problems
  sending your mail. If your internet link is down when you send mail,
  then the mail sits in "/var/spool/smail/input". When the link next
  comes up, "runq" is run which causes the mail to be sent. However,
  receiving mail is the problem since your provider has many clients to
  look after, not only you!

  Usually, you can retrieve your mail via the POP protocol, see POP
  section below.


  6.3.  OUTDATED SECTION: Sendmail+IDA


  For big sites, sendmail is worth choosing, due to the "incredible ease
  of use", (very relative feeling when you know qmail) but you must
  decide which you want between sendmail+IDA and sendmail 8.x:


  �  If you use an old kernel (1.0): sendmail+IDA

  �  If you use a not so old kernel (1.2): sendmail+IDA and source code
     editing

  �  Recent kernel (2.0) will choose sendmail 8.x

  Remember, linux newbies or people concerned by security / ease of
  configuration should rather try using smail or qmail, which are easier
  to use and safer.
  6.3.1.  Source installation


  If your distribution doesn't provide you with a ready-to-install
  sendmail package (.rpm for RedHat, Caldera and Suse, .deb for Debian)
  just download the sources and run:


  �  cd / ; tar -zxvf sendmail5.67b+IDA1.5.tgz


  �  cd to /usr/local/lib/mail/CF and copy the sample.m4 local.m4 file
     to "yourhostname.m4".

  Edit out the distributed hostname, aliases, smarthost and put in the
  correct one for your site. The default file is for a uucp-only site
  (no longer in 8.x) who has domainized headers and who talks to a smart
  host.  Then "make yourhostname.cf" and move the resulting file to
  /etc/sendmail.cf


  �  if you are uucp-only, you do *NOT* need to create any of the tables
     mentioned in the README.linux file.

  You'll just have to touch the files so that the Makefile works. Just
  edit the .m4 file, make sendmail.cf and start testing it.


  �  if you're uucp-only and you talk to sites in addition to your
     "smart-host", you'll need to add uucpxtable entries for each (or
     mail to them will also go through the smart host) and run dbm
     against the revised uucpxtable.


  �  If you run Rich Braun's original binary distribution of 5.67a,
     you'll need to freeze the configuration if you change your .cf file
     with "/usr/lib/sendmail -bz" to make the changes take effect.

  You should also update your version to at least 5.67b since there is a
  nasty security hole in 5.67a and earlier. Another nice thing is that
  if you have mail.debug set and you run syslogd, your incoming and
  outgoing mail messages will get logged. See the "/etc/syslog.conf"
  file for details.

  The sources for sendmail+IDA can be found at vixen.cso.uiuc.edu ; they
  require no patching to run under Linux if you're running something
  like a kernel of 1.00.

  If you're running a kernel > 1.1.50, you get the fun of reversing most
  of the Linux-specific patches that are now in the vanilla sources.  (I
  *did* told you this sendmail was only for old kernels:-)

  It's extremely obvious where this needs to be done: just type "make"
  and when it blows up, go to that line in the sources and comment out
  the Linux-specific code that's in there.

  If you're going to run sendmail+IDA, I strongly recommend you go to
  the sendmail5.67b+IDA1.5 version since all required Linux-specific
  patches are now in the vanilla sources and several security holes have
  been plugged that WERE (!!!) in the older version you may have grabbed
  or built before about December 1st, 1993.

  Now linux kernel is 2.0, you should use sendmail 8.x instead of
  sendmail+IDA, but I already told you'd better choose sendmail 8.x:-)


  6.3.2.  The sendmail.m4 file


  Sendmail+IDA requires you to set up a sendmail.m4 file rather than
  editing the sendmail.cffile directly.  The nice thing about this is
  that it is simple to set up mail configurations that are extremely
  difficult (if not totally impossible for most people to set up
  correctly) in smail or traditional sendmail.

  The sendmail.m4 file that corresponds to the above smail example looks
  like the following:


    dnl #------------------ SAMPLE SENDMAIL.M4 FILE ------------------
    dnl #
    dnl # (the string 'dnl' is the m4 equivalent of commenting out a line)
    dnl # (well, not exactly, but use it for this purpose if you must :-)
    dnl # you generally don't want to override LIBDIR from the compiled in paths
    dnl #define(LIBDIR,/usr/local/lib/mail)dnl    # where all support files go
    define(LOCAL_MAILER_DEF, mailers.linux)dnl    # mailer for local delivery
    define(POSTMASTERBOUNCE)dnl                   # postmaster gets bounces
    define(PSEUDODOMAINS, BITNET UUCP)dnl         # don't try DNS on these
    dnl #
    dnl #-------------------------------------------------------------
    dnl #
    dnl # names we're known by
    define(PSEUDONYMS, myhostname.subdomain.domain myhostname.UUCP)
    dnl #
    dnl # our primary name
    define(HOSTNAME, myhostname.subdomain.domain)
    dnl #
    dnl # our uucp name
    define(UUCPNAME, myhostname)dnl
    dnl #
    dnl #-------------------------------------------------------------
    dnl #
    define(UUCPNODES, |uuname|sort|uniq)dnl       # our uucp neighbors
    define(BANGIMPLIESUUCP)dnl                    # make certain that uucp
    define(BANGONLYUUCP)dnl                       #  mail is treated correctly
    define(RELAY_HOST, my_uucp_neighbor)dnl       # our smart relay host
    define(RELAY_MAILER, UUCP-A)dnl               # we reach moria via uucp
    dnl #
    dnl #--------------------------------------------------------------------
    dnl #
    dnl # the various dbm lookup tables
    dnl #
    define(ALIASES, LIBDIR/aliases)dnl            # system aliases
    define(DOMAINTABLE, LIBDIR/domaintable)dnl    # domainize hosts
    define(PATHTABLE, LIBDIR/pathtable)dnl        # paths database
    define(GENERICFROM, LIBDIR/generics)dnl       # generic from addresses
    define(MAILERTABLE, LIBDIR/mailertable)dnl    # mailers per host or domain
    define(UUCPXTABLE, LIBDIR/uucpxtable)dnl      # paths to hosts we feed
    define(UUCPRELAYS, LIBDIR/uucprelays)dnl      # short-circuit paths
    dnl #
    dnl #--------------------------------------------------------------------
    dnl #
    dnl # include the 'real' code that makes it all work
    dnl # (provided with the source code)
    dnl #
    include(Sendmail.mc)dnl                         # REQUIRED ENTRY!!!
    dnl #
    dnl #------------ END OF SAMPLE SENDMAIL.M4 FILE -------



  6.3.3.  Defining a local mailer

  Unlike most Unix distributions, Linux did not come with a local mail
  delivery agent by default.

  Slackware did!  Well at least it is offered by the easy-to-use-but-
  longwinded installation script.  It uses procmail.

  Now, deliver or procmail is generally installed, with a default
  sendmail setup to handle local mail, so no complexity will be added to
  this already very complex setup. I recommend using the commonly
  available deliver or procmail programs, which can be optional packages
  in a some Linux distributions.

  In order to do so, you need to define a LOCAL_MAILER_DEF in the
  sendmail.m4 file that points to a file that looks like:


    # -- /usr/local/lib/mail/mailers.linux --
    #     (local mailers for use on Linux )
    Mlocal, P=/usr/bin/deliver, F=SlsmFDMP, S=10, R=25/10, A=deliver $u
    Mprog,  P=/bin/sh,       F=lsDFMeuP,   S=10, R=10, A=sh -c $u



  There is a also built-in default for deliver in the Sendmail.mc file
  that gets included into the sendmail.cf file. To specify it, you would
  not use the mailers.linux file but would instead define the following
  in your sendmail.m4 file:


     dnl --- (in sendmail.m4) ---
     define(LOCAL_MAILER_DEF, DELIVER)dnl       # mailer for local delivery



  Unfortunately, Sendmail.mc assumes deliver is installed in /bin, which
  is not the case with Slackware1.1.1 (which installs it in /usr/bin).
  In that case you'd need to either fake it with a link or rebuild
  deliver from sources so that it resides in /bin. Please note procmail
  is generally better than deliver, for example for mail filtering.


  6.3.4.  The sendmail+IDA dbm tables


  Setting up special behavior for sites or domains is done through a
  number of optional dbm tables rather than editing the sendmail.cf file
  directly.

  Refer to the July-1994 issue of Linux Journal (if you can still find
  it:-), to the docs in the sources, or to the sendmail chapter in the
  newest version of the Linux Documentation Project Networking
  Administration Guide which will be available real-soon-now for more
  details.


  �  mailertable   - defines special behavior for remote hosts or
     domains.

  �  uucpxtable    - forces UUCP delivery of mail to hosts that are in
     DNS format.

  �  pathtable     - defines UUCP bang-paths to remote hosts or domains.


  �  uucprelays    - short-circuits the pathalias path to well-known
     remote hosts.

  �  genericfrom   - converts internal addresses into generic ones
     visible to the outside world.

  �  xaliases      - converts generic addresses to/from valid internal
     ones.

  �  decnetxtable  - converts RFC-822 addresses to DECnet-style
     addresses.


  6.3.5.  So which entries are really required?

  When not using any of the optional dbm tables, sendmail delivers mail
  via the RELAY_HOST and RELAY_MAILER) defined in the sendmail.m4 file
  used to generate sendmail.cf. It is easily possible to override this
  behavior through entries in the domaintable or uucpxtable.

  A generic site that is on Internet and speaks Domain Name Service, or
  one that is UUCP-only and forwards all mail via UUCP through a smart
  RELAY_HOST, probably does not need any specific table entries at all.

  Virtually all systems should set the DEFAULT_HOST and PSEUDONYMS
  macros, which define the canonical site name and aliases it is known
  by.

  If all you have is a relay host and relay mailer, you don't need to
  set these defaults since it works automagically. UUCP hosts will
  probably also need to set UUCPNAME to their official UUCP name.

  They will also probably set RELAY_MAILER and RELAY_HOST which enable
  smart-host routing through a mail relay.

  The mail transport to be used is defined in RELAY_MAILER and should
  usually be UUCP-A for UUCP sites. If your site is SMTP-only and talks
  `Domain Name Service', you would change the RELAY_MAILER.

  If you're a SLIP site, you might want to take the easy way out and
  just forward all outgoing mail to your service provider to do the
  right thing with.  To do so, you'd want to define ISOLATED_DOMAINS and
  VALIDATION_DOMAINS to be your domain, you'd also want to define
  RELAY_HOST to be your service provider and RELAY_MAILER to be TCP. Of
  course, you want to ask permission before you set any system up as
  your general purpose relay.


  6.4.  Sendmail 8.x


  Sendmail 8.7.x from Berkeley was the latest major revision after
  sendmail5. It had wonderful built-in support for building under Linux
  : just "make linux" and all was set.

  You'll probably be best served by grabbing one of the various binary
  distributions off of the usual Linux archive sites rather than
  fighting things like Berkeley dbm yourself.

  There's a nice distribution of sendmail 8.6.12 from Jason Haar -
  j.haar at lazerjem.demon.co.uk  on sunsite.unc.edu in
  /pub/Linux/system/Mail/delivery/sendmail-8.6.12-bin.tgz that has the
  source documentation and a very nice quickie description of how to run
  sendmail v8 for common configurations.


  The bottom line with sendmail v8 is that you want to configure the
  bare minimum necessary to get the job done ; the following is an
  example that should get you close at least.


  6.4.1.  A sample 8.7.x mc file


  Much like sendmail+IDA, sendmail v8 uses m4 to process a config file
  into a full sendmail.cf that sendmail uses.  The following is my
  current mc file for my site (ppp to Internet for outgoing mail, uucp
  for incoming mail).


          dnl divert(-1)
          #---------------------------------------------------------------------
          #
          # this is the .mc file for a linux host that's set up as follows:
          #
          #       - connected to Internet for outbound mail (ppp here)
          #       - connected via UUCP for incoming mail
          #       - domainized headers
          #       - no local mailer (use 'deliver' instead)
          #       - no DNS running so don't canonicalize outgoing via DNS
          #       - all non-local outbound mail goes to the RELAY_HOST over smtp
          #           (we run ppp and let our service provider do the work)
          #
          #                                       vds 3/31/95
          #
          #---------------------------------------------------------------------
          include(`../m4/cf.m4')
          VERSIONID(`linux nodns relays to slip service provider smarthost')dnl
          Cwmyhostname.myprimary.domain myhostname.UUCP localhost
          OSTYPE(linux)
          FEATURE(nodns)dnl
          FEATURE(always_add_domain)dnl
          FEATURE(redirect)
          FEATURE(nocanonify)
          dnl MAILER(local)dnl
          MAILER(smtp)dnl
          MAILER(uucp)dnl
          define(`RELAY_HOST', smtp:my.relay.host.domain)
          define(`SMART_HOST', smtp:my.relay.host.domain)
          define(`UUCP_RELAY', smtp:my.relay.host.domain)
          define(`LOCAL_MAILER_PATH', `/bin/deliver')
          define(`LOCAL_MAILER_ARGS', `deliver $u')



  6.4.2.  Sendmail v8 tidbits


  There are a few differences I suppose to the 'IDA bigots' among us.
  So far, I've found the following:


  Instead of 'runq', you type 'sendmail -q' to run the queue!



  6.5.  Local Delivery Agents


  Unlike most operating systems, Linux did not have mail "built-in": you
  needed a program to deliver the local mail, like "lmail", "procmail"
  or "deliver".

  However, every recent distribution includes a local mailer now!

  Documentation for how to use either for local delivery is in the
  sendmail5.67b+IDA1.5 binary release (on sunsite) mentioned above.


  7.  User Agent Administration



  7.1.  Mutt


  You should have no problem compiling, installing, or running mutt.
  Users of qmail can either get the patch or run it with -f flag to read
  their local mail folder.

  If mutt bothers you with an "unknown terminal error" after a
  distribution upgrading, just recompile it.


  7.2.  Elm


  Elm compiles, installs and runs flawlessly under Linux. For more
  information, see the elm sources and installation instructions. Elm
  and filter need to be mode 2755 (group mail) with /var/spool/mail mode
  775 and group mail.

  Qmail users can get a patch to use nifty qmail features, or will run
  elm with the -f flag to point to their local mail folder.

  One thing you want to be aware of is that if you have Elm compiled to
  be MIME-able, you need metamail installed and in the standard path or
  Elm will not be able to read MIME mail you've received.  Metamail is
  available on thumper.bellcore.com and of course via "archie".

  If you use a binary distribution, you'll need to create a
  "/usr/local/lib/elm/elm.rc" file to override the compiled-in hostname
  and domain information:


  �  replace "subdomain.domain" with your domain name replace

  �  "myhostname" with you un-domainized hostname replace


          #---------- /usr/local/lib/elm/elm.rc ------------------
          #
          # this is the unqualified hostname
          hostname = myhostname
          #
          # this is the local domain
          hostdomain = subdomain.domain
          #
          # this is the fully qualified hostname
          hostfullname = myhostname.subdomain.domain
          #
          #--------------------------------------------------------



  One thing you want to be aware of is that if you have Elm compiled to
  be MIME enabled, you need metamail installed and in your path or Elm
  will not be able to read MIME mail you've received. Metamail is
  available on thumper.bellcore.com and of course via "archie".

  In the "too cool to be true" category, there is a distribution of
  Elm-2.4.24 that is "PGP-aware". To try it, grab the file
  ftp://ftp.viewlogic.com/pub/elm-2.4pl24pgp3.tar.gz, which is elm2.4.24
  with PGP hooks added. You configure and build it the same way you do
  normal Elm, which means you probably need to add the patches mentioned
  above. For what it's worth, I run it here and like it a lot. Of
  course, there must be more recent versions available, including elm-
  ME+.

  While this item is not Linux-specific, it's perceived (wrongly) to be
  a nagging Elm bug nevertheless.  We've heard that Elm sometimes fails
  with a message that it's unable to malloc() some massive number of
  bytes.  The identified workaround is to remove the post-processed
  global mail aliases (aliases.dir and aliases.pag).

  THIS IS NOT A BUG IN ELM, it's an error in configuration of Elm by
  whomever you got your binary distribution of Elm from.

  Elm has an enhanced and non-compatible, format for aliases ; you need
  to ensure that the path Elm uses for aliases is different from the
  path sendmail/smail uses. From the volume of reports of this problem,
  it's apparent that at least one major distribution 'on the street' has
  in the past been misconfigured. (from  scot at catzen.gun.de (Scot W.
  Stevenson) )

  The current metamail package requires csh for some of its scripts.
  Failure to have csh (or tcsh) will cause most interesting errors...


  7.3.  Mailx


  If you don't have a local mailx program, save yourself the pain --
  just go and grab the mailx kit from Slackware 2.1.0 or later, which
  has a nice implementation of mailx5.5. If you're into building from
  sources, mailx v5.5 compiles without patching under Linux if you have
  "pmake" installed.

  If anybody is still using it, I strongly recommend removing the old
  "edmail" stuff from SLS1.00 and replacing it with mailx.


  8.  Handling remote mail


  This section describes using POP or IMAP to handle remote mail.

  Other options include nfs-mounting the spool partition on client
  machines (Danger Will Robinson! Is everyone using the same lock
  method?) or using a mail-to-web gateway (quite popular now).


  8.1.  History


  On a workstation network, mail has always been a problem:


  �  Either you use "user@computer.foo.com" with problems when
     "computer" is down, making your network known to the people
     outside, having different addresses for a same person switching to
     another computer, ...

  �  Or you take a mail hub, "mailhost.foo.com" with rules for
     rewriting, so every user seems to post from the same address, even
     if they are on different computers.

  But in that case, how can users read their mail?

  Using a rsh with elm? :-)

  It would overload our mail hub!  One method was forwarding or UUCP,
  smtp, etc. but it's too complicated.

  Then came POP/IMAP, both with security problems at the beginning, (now
  fixed using ssh on new versions): a mail program has sometimes to be
  set locally (like qmail, smail or vmail if, for example, you use elm,
  but mozilla will avoid that!) however, getting and sending Email is
  simpler.


  8.2.  Getting mail


  Here come POP's main drawbacks:


  �  the password is sent as a clear text on the network,

  �  you must choose a POP-aware mailer; many do now (like Pine, Emacs,
     Mozilla, Netscape, Mutt, IE, Pegasus, Eudora, Claris...),

  �  when a user may roam (read mail from different machines) having e-
     mail popped on the computer used yesterday can be a nuisance,

  �  some POP servers (e.g. qpopper, ipop3d) on high-use servers can
     load the machine significantly. Consider controlling options (such
     as not leaving mail on the server) and/or changing the pop server
     (e.g. cucipop), as well as avoiding running it from inetd.

  The password problem can be solved creating a crypted "channel" to
  have POP on it or using APOP or RPOP extensions. The mail reader
  problem can be solved either by changing mail reader (don't
  underestimate the effort required to re-educate users!) or by using a
  POP "mail sucker" with a local mail program.

  IMAP can be preferable to POP in various situations like remote (and
  especially roaming) access, while you restrict POP to a LAN where
  snooping of passwords isn't so much of a concern.  Mark Aitchison
  reported a solution here is to use hosts.deny and hosts.allow files
  (please see Net-3 HOWTO ; this assumes you are starting pop from
  inet).

  The policy of leaving mail on the server or not has implications for
  server disk space and easier backup/security of the mail, as well as
  allowing roaming, so the best solution depends on the type of
  organization. Of course, this will not ensure your mail can't be read,
  but nobody will be able to delete it ; if all your mail is pgp
  encrypted this is a better solution.

  Here are some pop programs worth trying:


  �  gwpop (a Good Way to POP) is very protected since it creates a
     crypted "channel" and puts mail directly in the "spool" ; however,
     it depends on Perl.

  �  popclient, simple to use:

     For example if your login is john and your password PrettySecret,
     you will run:



       $ popclient -3 -v mail.acme.net -u john -p "PrettySecret" -k -o JOHN-INET-MAIL



  It is strongly discouraged in case of multi-user machine; other user
  can see your password by, for example with "ps auxw"

  �  fetchmail, which is actively supported and incredibly simple to
     use: it is configured in ~/.fetchmailrc, so you only need to run
     fetchmail when you want to retrive your mail.

     Here's my .fetchmailrc:


       poll mail.server protocol pop3:
               forcecr
               password PrettySecret;



  Don't forget to "chmod 600  /.fetchmailrc" or fetchmail will ask for
  it.

  Please note that the forcecr option is needed to use fetchmail with
  qmail, which strictly respects RFCs.


  8.3.  Sending mail


  For this, you must use smtp-aware mail software, like qmail, smail,
  vmail or mozilla (this one does everything: mail reader, POP receive,
  smtp send!)

  Go to one of the previous sections to install and configure the one
  you like best. Then, when you will reach "Testing", try to send some
  mail to a local account on the mail hub.


  8.4.  Reading mail


  If your program doesn't do everything itself, you can install elm,
  pgp, mush, pine ... many good programs are freely available for linux
  platforms!


  8.5.  Testing


  To check whether your mail server has pop, try:



       $ telnet mailhost 110


  If it works, you will get something like "OK Pop server (...)
  starting": type "quit"!

  To install a ssh crypted "channel", first test your mail server
  typing:



       $ ssh mailhost date



  If you get the date, you should be OK. Please note ssh will not ask
  for a password, therefore you must create a ".shosts" file on the mail
  server, containing client's name. To test ssh port redirection (which
  gwpop uses), type:



       $ ssh -n -f -L 12314:localhost:110 mailhost sleep 30

       then

       $ telnet localhost 12314



  Then will you hopefully see mail hub's pop banner. If you don't use
  ssh, don't forget to comment out $ssh on gwpop script. To check
  whether procmail is running, try "procmail -v"


  8.6.  Using


  Now you can edit gwpop Perl script to check everything is ok, then run
  gwpop:



       $ gwpop -v your-username
       POP password on mailhost: yoursecretpasword



  If gwpop "error messages" are normal, the mail from mail hub will be
  downloaded to your local machine wherever you told gwpop to put it.
  (please test with some mail!).

  You can also use gwpop as a daemon:



       $ gwpop -d $HOME/tmp your-username



  gwpop messages are then sent to syslog and gwpop will run endlessly ;
  a "HUP" signal will force gwpop to get your mail.

  You can get POP software here used on:

  ftp://ftp.unina.it/pub/Unix/pkgs/network/mail/gwpop
  ftp://ftp.informatik.rwth-aachen.de/pub/packages/procmail
  http://www.cs.hut.fi/ssh/



  9.  Acknowledgements


  The following people have helped in the assembly of the information
  and experience that helped make this document possible:

  Steve Robbins, Ian Kluft, Rich Braun, Ian Jackson, Syd Weinstein, Ralf
  Sauther, Martin White, Matt Welsh, Ralph Sims, Phil Hughes, Scot
  Stevenson, Neil Parker, Stephane Bortzmayer and especially many thanks
  to Vince Skahan for his huge contribution.

  Eric S. Raymond edited this document, correcting some mistakes and
  transplanting the section on ``How Electronic Mail Works'' from his
  Mail User's HOWTO.

  Hitoshi Hayakawa checked qmail section, Jun Morimoto added various
  notes about popclient & fetchmail and Takeo Nakano ispell'ed the
  document :-)


  If I forgot anybody, my apologies: just email me!







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