[Mailman-Users] How Mailman related to...

J C Lawrence claw at kanga.nu
Thu Jul 5 06:41:37 CEST 2001

On Wed, 04 Jul 2001 13:41:46 -0700 
Charles Iliya Krempeaux <tnt at linux.ca> wrote:

> Specifically, how it relates to other pieces of software.  For
> example, how does Mailman relate to pieces of software like
> Sendmail, Qmail, exim, and PostFix?  

Sendmail, QMail, exim, postfix et al are MTAs, Mail Transfer Agents.
Mailman is an MLM Mailing List Manager.  Mailman takes a message
delivered to it by and MTA, proceses it, generates some number of
messages addressed to the members of the list, and hands those
messages back to the MTA.  The MTA then arranges delivery of those
messages as applicable.

> In my (probably naive) understanding, these are the actual Mail
> Servers.  

They are MTAs.  The term "mail server" is imprecise at best and
actively ambiguous at worst.

> They are the SMTP server, and the POP3 or IMAP server.  

No, they are the MTAs and they are responsible for processing and
generating SMTP connections.  POP3 and IMAP servers are quite
unrelated both architecturally and in function.  

POP3 and IMAP servers process a mail store -- a place mail is stored
for retrieval and use (not transport) -- and represent/present that
mail store out to client systems via a defined protocol (POP3 or
IMPA).  POP3 and IMAP servers are not responsible for or active in
the transfer or receipt of messages either between users or systems.

> Does Mailman work with these?... as an add-on?  

Mailman is a mail processing system.  It received messages from an
MTA, processes them, and may (or not) generate new messages which it
hands back to an MTA.  Very simple really.

> Or does it replace these?

There's no functional overlap between Mailman and the other
applications you've mentioned.

> Also, how does Mailman relate to something like Procmail.  

Procmail is two things:  

  Procmail is an example of a Local Delivery Agent (LDA), which is
  the tool/process/program responsible for delivering a message
  received by an MTA to a local user acount or process.  LDAs are
  run by an MTA when it realises that a given message has arrived at
  its destination system and needs to be handled locally somehow.

  Procmail is a mail filtering tool.  It can do this as part of its
  LDA duties, but many also use this as part of mail automation
  systems after the LDA has processed a message and "sent" it to the
  appropriate local mail store.  Procmail has the ability to extract
  various data from messages, compare them, and make decisions based
  on those comparisons.  It also has the ability to run external
  programs against a given message.

> (Not that I completely understand how Procmail works.  But I
> believe it is an add-on to Sendmail, that does various kinds of
> filtering.)

Procmail is not an add-on to sendmail.  Procmail can be used with
sendmail as the LDA but does not need to be.  Sendmail also comes
packaged with a default small-featured LDA.  Many people muddy the
waters here by using their MTA's default LDA to pass messages to
procmail for final delivery/handling.  ie:


This is usually done through a ".forward" file in their home
directory which the MTA's LDA looks for, recognises, and processes
the contents of to deliver a message.  A sample .forward might

  "| procmail -f -"

Which instructs the LDA to pass the current message to procmail on stdin.

J C Lawrence                                             claw at kanga.nu
---------(*)                                http://www.kanga.nu/~claw/
I never claimed to be human.

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