[rescue] Mail Server

Mike Meredith mike at redhairy1.demon.co.uk
Tue Dec 21 12:12:55 CST 2004

On Tue, 21 Dec 2004 08:31:42 -0600, Wes Will wrote:
> 4.  Exim and qmail are quite able programs, and Exim in particular is
> known for dealing gracefully with very large loads by using some
> decent parallel queueing strategies.  Both programs (and qmail

Eh? That's the thing Exim is not known for ... queueing I mean, as it
quite happily handles quite extreme levels of load. Exim was written on
the assumption that the vast majority of mail can be delivered
immediately with only a tiny amount being put onto the queue for later
delivery attempts. In fact the subject of handling large queues appeared
on the Exim mailing list recently, and there's a chance that something
will be done about it.

For the record, unless you're handling millions of messages a day Exim
will work perfectly well without tuning.

> especially) are difficult to get set up.  It takes some getting used

Exim is difficult to setup ? Blimey, I must be brighter than I thought

> to to blithely put binaries in /var.... In other words, getting either

Most people stick the Exim binaries in the normal places for binaries. I
suppose you could stick 'em under /var if you wanted to, but why?

> around - and we're back to to the binaries in/var thing... I just
> don't -like- qmail.).

There's lots of legitimate reasons for not running qmail. For instance,
it seems by default to bounce undeliverables rather than reject them.
And it doesn't collapse multiple recipients into one SMTP session.

> There are some reasons, not too rabid, for Postfix.  If you are
> needing something in the small-to-medium-huge range, Postfix is your

I'd choose Exim myself, but I certainly wouldn't panic at running

> best bet.  If you want to handle massively huge mail queues (tens of
> thousands of messages per minute), go with Exim and pay close
> attention to the process and thread limits sections of the config

There's a *threads* section ? Doesn't appear in my Exim configuration
file which isn't conclusive, but I did pay a lot of attention when
writing it.

And get the fastest disks you can for your /var (or /var/spool/exim).
Preferably solid state disks. One guy wanted to use IDE disks on his
Exim server; I fell off my chair laughing.

I've got to admit I'm puzzled by why you think that Exim is hard to
configure. Sure it isn't that easy, but no MTA is really easy (if you
think it is, you're probably doing something wrong).

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