Author: Jürgen Herz Date: To: exim-users Subject: Re: [exim] does exim run as root or not?
> Not having looked at the Exim source code recently, I can't be > authoritative. But I believe that Exim starts running as root, examines
> its command options, and then changes its user-id.
>
> So, the Exim mail server daemon launches as root, binds to port 25, and
> then becomes user exim. To deliver mail to a particular user (since
> Exim has lost root), it starts running a *new* Exim.
Thanks Jonathan and also Philip for your helpful answers!
I suspected that there are more than one Exim instances but ps didn't
show them. My error was thinking they must be around all the time or
spawn from the daemon. I missed that the listener daemon could just
start the binary once again and this will be root thanks to suid.