Re: [Exim] EXIM_USER value in Makefile during building

On Tue, 29 Apr 2003 10:54:15 +0100 Wei wrote:

> So if a certain user "john" on my linux box wants to fetch email
> from an email address like wei@???
> Then I should set EXIM_USER=wei@??? ?

I think you are missing the point big-time here. EXIM_USER is the name of
a UNIX user which the Exim daemon will (mostly) run with the permissions
of. It's definitely not an e-mail address and is not related to the
handling of e-mails. It's just a relatively unprivileged user, independent
of the "real" users on your system. The reason why Nico told you not to
use root is that this would then give the Exim daemon superuser privileges
on your system, which is not necessary and universally considered a very
bad idea, primarily from a security point of view.

What you need to understand is that EXIM_USER is quite a "low-level"
setting (for want of a better description). It basically sets the
operating system-level privileges that the Exim SMTP daemon (server) will
have when running. All the configuration about what domains/email
addresses/etc. you will handle and how this is done is done at a later
stage via the runtime configuration file exim.conf.

Basically, don't get bogged down too much with this EXIM_USER setting. You
just need to do create a new UNIX user "exim" and then set EXIM_USER=exim,
or, as Nico said, you could use the user "mail" which is commonly set up
on many systems for this purpose. Then compile Exim and (more or less)
forget about it.

What system are you using BTW? Red Hat? Debian? Something else?

Have you read the Exim manual? This explains installation, configuration
etc. in quite some detail.

> every user on my linux box has to configure, build
> and install his/her own copy of Exim with setting the EXIM_USER as
> his/her own email address?

Definitely not.

> My naive understanding about this was that "fetchmail" would indicate
> which email address to fetch email from, where each user
> on my linux box could set his/her own email address in the personal
> .fetchmailrc file. Then all my linux box's users' email would all
> be sent to port 25 where Exim is acting as an SMTP server, listening at
> port 25. In that case, there should only be one SMTP server running
> on my linux box.

Yes, you're more or less right here (assuming you want to fetch some mail
via POP/IMAP/etc from a remote server with fetchmail, and deliver it to a
local user). You can have many users with fetchmail, all with their own
preferences etc. Then fetchmail will (depending on your settings) connect
to the SMTP server (Exim, running as user "exim" if you set it up that
way) and will send the mails on, indicating in the SMTP RCPT command (this
is part of the SMTP dialogue) which user the mail is destined for. What
happens to it from then on depends on how you have set up exim.conf, but
let's cross that bridge when we come to it - get Exim compiled and
installed first.


Tim