[plug] mta differences

[James Devenish]

Hi,

The Maildir format itself does not differ between MTAs -- it is a format
unto itself. (Though some MTAs may supplement a Maildir with indices.)

In message <20040416090216.GSJI27218.swebmail00.mail.ozemail.net at localhost>
on Fri, Apr 16, 2004 at 07:02:16PM +1000, smclevie at ozemail.com.au wrote:
> Then I send mail by,
> echo "To: johnny" | /usr/sbin/sendmail

By the way: something that strikes me is that the above line is
MTA-specific. (The "sendmail" command is actually provided by the MTA
even though most MTAs are not actually called 'sendmail'.) I would
think that the more traditional usage would be:
% echo Subject: test1 | /usr/sbin/sendmail johnny
(If you were to supply the recipient in a 'To:' line, I would think that
you should use the -t option for the 'sendmail' command.) However, this
issue shouldn't impact in any way on your problem with mailbox formats.

> and when I went back to see the directory againwith,
> ls -al
> on the /var/mail directory I could see that the johnny 'directory' was now a file!!

That sounds scary to me. I would have thought that makemaildir would
have created 'johnny' with three subdirectories: 'new', 'cur' and 'tmp'.
Do you mean that there was a file /within/ the 'johnny' directory, or
that the previous 'johnny' directory had been deleted and replaced with
a file? It sounds like you mean the latter. That sounds scary to me.
Anyone care to explain? I can't quite imagine how an MDA or MTA could
decide to delete 'johnny' and its subdirectories. But if this /is/ the
case, it sounds like courier doesn't "understand" different mailbox
formats and supersedes any existing structures with mbox files. Eek. I
have heard bad things about courier, and I guess this can be added to
the list.

> I can't download though to the mailbox...

When you say "download", do you mean you are using POP? Is it one that
is supplied by 'courier'? Perhaps it cannot understand Maildir, or it is
not configured to allow Maildir.

> When postfix is installed instead of courier I get a directory with
> 'new' and 'cur' etc.etc.  But I lose the ability to send mail to a
> user on the local machine and I can't download into the mailbox
> etc.etc.

(Not sure quite what you mean by "[loss of] ability to send".)

> This interaction between MTA's and Pop servers etc seems to be a
> rather broken idea at this point in time, yes??

Take this flow diagram:

mail delivery agent (MDA) -> server spool -> POP -> client mailbox

With UNIX systems, the MDA and POP servers are generally two completely
separate software products, and both understand the spool format. The
spools might be 'mbox' or 'MH' or 'Maildir' or whatever. What this means
is that the MDA (or MTA) and POP servers must both understand the spool
format. I'm not sure why you would have trouble with this, but on the
face of it I would guess that Courier does not understand Maildir.