Re: [exim] Exim & Spamassassin at SMTP time

On Tue, Mar 09, 2010 at 11:40:20AM +0000, Ian Eiloart wrote:
> > Can Exim support 'virtual' domains with this kind of scenario:
> > Accept mail for catchall@domain for virtual mailbox on the local machine
> > Accept mail for catchall@domain and relay to a final destination server
> > Accept mail for x.recipient@domain1 and deliver to local virtual mailbox
> > Accept mail for y.recipient@domain1 and relay to remote final
> > destination.
>
> Yes, you can do all those things. However, you'd be advised
> against using catchall mailboxes. It's probably better to use
> plus-addressing if you want to assign a range of addresses in
> advance.

Agreed - catchall addresses will mean you have more spam to deal
with, and someone who gets your address wrong by mistake won't
know that you might delete it without reading it (because of the
spam). That's one reason anyway.

My home mail is too complex, but gives an idea of what is
possible. Because of the complexity, I might have got this a bit
wrong, but in essence:

For each local address, it looks up in a text table to see if the
domain is local, and also see if there is a "folder name"
associated with that domain. If so, that returns the name of an
'aliases' file for that domain.

The aliases file is then looked up, to see what local user (or
remote address) the mail should be delivered to. If remote, it is
sent on.

For local users, if the local part is plain, it is delivered to
their inbox.

If the local part has a suffix (e.g. matthew-exim), then Exim will
look in their Maildir and see if a sub-folder of the suffix name
(here, "exim") exists under the previously looked up "folder name"
for that domain.

If this sub-folder exists, the mail is delivered there, otherwise
the mail is rejected (at SMTP time).

This allows users (OK, my Wife and I!) to create an IMAP folder in
the mail client, and then an e-mail address is automatically
created to drop mail into that folder. Delete the folder, the
address goes away.

I wouldn't necessarily recommend this, but exim makes it possible;
not just to do the delivery into wierd folders, but to do it when
receiving the mail, so that it can be rejected at SMTP time if it
can't be delivered and not bounce.

Cheers,

Matthew


--
Matthew Newton, Ph.D. <mcn4@???>

Systems Architect (UNIX and Networks), Network Services,
I.T. Services, University of Leicester, Leicester LE1 7RH, United Kingdom

For IT help contact helpdesk extn. 2253, <ithelp@???>