IMAP - non-user email addresses

Justin C · External Since: Jun 01, 2007 Posts: 10

Currently, non-user email addresses are aliased in /etc/aliases here,
and mail is collected using POP3. I need to change the set up so that
mail to these addresses is delivered using IMAP so they can be picked
up by whoever is available, rather than waiting for the aliased user
to check their mail.

Exim 4.64 is our mailserver, and we're running with a monolithic
config file.

I'm not sure how to have exim receive mail for non-existent users. Also,
I don't want it to receive mail for *all* non-existent addresses, sales,
admin, accounts, buyer, etc., are OK, but I don't want to handle
viagra@, or similar!

Thank you for any suggestions.

Justin.

--
Justin Catterall www.masonsmusic.co.uk
Director T: +44 (0)1424 427562
Masons Music Ltd F: +44 (0)1424 434362
For full company details see our web site

Nigel Wade · External Since: Mar 30, 2004 Posts: 35

Justin C wrote:

> Currently, non-user email addresses are aliased in /etc/aliases here,
> and mail is collected using POP3. I need to change the set up so that
> mail to these addresses is delivered using IMAP so they can be picked
> up by whoever is available, rather than waiting for the aliased user
> to check their mail.

IMAP is a protocol for reading mail. What you probably want is an IMAP server
which supports shared folders to read the messages.

>
> Exim 4.64 is our mailserver, and we're running with a monolithic
> config file.

To my knowledge that's the only type of config. file which Exim uses. I know the
Debian Exim package has gone its own way, but that's Debian, not Exim.

>
> I'm not sure how to have exim receive mail for non-existent users.

It won't. You have to convince Exim that the users exist, but that's not a
problem. /etc/aliases is one way. All Exim requires to validate a recipient is
a router which accepts the recipient. Any router will do. You can validate
recipients in LDAP, from your favourite database, stored in a text file or even
write your own external Perl module to do it if you really, really want to.

The router which verifies the recipient should also specify a transport for
delivery of the mail. This transport will have to know how to store the
messages for a non-existent user. Obviously it can't be in any of the usual
places.

> Also,
> I don't want it to receive mail for *all* non-existent addresses, sales,
> admin, accounts, buyer, etc., are OK, but I don't want to handle
> viagra@, or similar!
>

You won't, unless you make a mistake...

--
Nigel Wade

Chris Davies · External Since: Apr 13, 2004 Posts: 267

Justin C <justin.0706.TakeThisOut@purestblue.com> wrote:
> Currently, non-user email addresses are aliased in /etc/aliases here,
> and mail is collected using POP3. I need to change the set up so that
> mail to these addresses is delivered using IMAP [...]

> Exim 4.64 is our mailserver [...]

I have just this setup. Exim delivers to a specified set of virtual
mailboxes, with dovecot serving users via POP3 and IMAP. The information
required to set this up is mostly in the dovecot wiki, but I reckon you
have to know your way around exim and dovecot - at least a little bit -
to make best use of it.

However, unless you're already using virtual user accounts, it's probably
going to be easiest just to create real accounts for these non-user
aliases (i.e. entries in /etc/passwd). Don't forget to the shell for
these accounts to /bin/false.

To get IMAP as well as POP3 I strongly suggest dovecot (it's pretty
simple to configure, and it sits well with exim). You'll need to disable
your existing POP3 service, obviously. On my (debian) system, dovecot's
configuration file is /etc/dovecot/dovecot.conf. The really important line
is the protocols entry, which you need to set to at least "protocols =
imap pop3". Take a look at http://wiki.dovecot.org/ for other
configuration details.

Hope this helps,
Chris

Justin C · External Since: Jul 06, 2007 Posts: 7

In article <8sojm4-efv.ln1.RemoveThis@news.roaima.co.uk>, Chris Davies wrote:
> Justin C <justin.0706.RemoveThis@purestblue.com> wrote:
>> Currently, non-user email addresses are aliased in /etc/aliases here,
>> and mail is collected using POP3. I need to change the set up so that
>> mail to these addresses is delivered using IMAP [...]
>
>> Exim 4.64 is our mailserver [...]
>
> I have just this setup. Exim delivers to a specified set of virtual
> mailboxes, with dovecot serving users via POP3 and IMAP. The information
> required to set this up is mostly in the dovecot wiki, but I reckon you
> have to know your way around exim and dovecot - at least a little bit -
> to make best use of it.
>
> However, unless you're already using virtual user accounts, it's probably
> going to be easiest just to create real accounts for these non-user
> aliases (i.e. entries in /etc/passwd). Don't forget to the shell for
> these accounts to /bin/false.

I took your advice here, sales is now a user account. You're right about it being the easiest way.

> To get IMAP as well as POP3 I strongly suggest dovecot (it's pretty
> simple to configure, and it sits well with exim). You'll need to disable
> your existing POP3 service, obviously. On my (debian) system, dovecot's
> configuration file is /etc/dovecot/dovecot.conf. The really important line
> is the protocols entry, which you need to set to at least "protocols =
> imap pop3". Take a look at http://wiki.dovecot.org/ for other
> configuration details.

As POP3 was already working fine, I didn't feel like messing around with it. I did install Dovecot, and just 'switched on' IMAP. The whole thing took me about ten minutes, including the apt-get install.

Thank you for your help with this.

Justin.

--
Justin C, by the sea.