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

J C Lawrence claw at kanga.nu
Thu Jul 5 08:51:23 CEST 2001

On Wed, 04 Jul 2001 22:24:20 -0700 
Charles Iliya Krempeaux <tnt at linux.ca> wrote:

> How exactly does a MLM (Mailing List Manager), like Mailman, get
> messages from a MTA?

The MTA hands the message to Mailman much as if it were an LDA.
Typically LDAs work by having the message piped to them on stdin.
In Mailman's case it receives the messages on the stdin of various
programs and responds accordingly.

> The way I am accustomed to seeing an MTA, like Sendmail work, is
> that it receives an e-mail, and then appends that e-mail to a
> user's mbox file.  

Not quite.  The MTA receives the message, likely from another MTA
via SMTP.  If the message is destined for a local address the MTA
then pipes the message to whatever the local LDA is.  That LDA then
(commonly) appends the message to that user's mbox file (if that's
the local configuration etc).

> So, is there a special `user account' made for Mailman,... and
> Mailman then looks at it's mbox file, and takes `care of business'
> that way?... or does it get given the e-mail messages in another
> manner.  

See above.

> Also, how does an MLM, like Mailman, handle the e-mail addresses
> used for the mailing lists?  I would imagine that it is the MTA
> that decides what happens for each e-mail address.  


> (For example, it could hand it off to the LDA because it knows the
> e-mail address belongs to a local user of the system.  Or it could
> reject the email address because that email address does not
> correspond to any user on the system.)  


> Do MLMs, like Mailman, simply provide some kind of `front end' or
> `abstraction' to the e-mail address handling facilities of the
> various different MTAs (like Sendmail, Qmail, exim, PostFix, etc,
> that) it works with?  

Yup.  This is commonly done via an alias file that maps email IDs to
process pipes.  In Mailman's case they map the various mailman-run
email addresses to programs that know how to handle messages piped
to them appropriately.

> (Or am I missing something?)

Some MTAs can be configured to work with mailman without use of an
alias file to do the address mapping.  This is not magic, what is
really happening is that the MTA configuration is faking an alias
file.  IT is looking at the local system in some way and computing
the result (eg pipe this message to that Mailman program) exactly as
if there were an alias file.

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

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