How to identify where messages come from on a small LAN

[Chris G]

On Sun, Nov 28, 2010 at 04:47:31PM +0000, Tony Pursell wrote:
> On Sun, 2010-11-28 at 15:50 +0000, Chris G wrote:
> > We have a small SoHo LAN with two Ubuntu 10.04 server machines, a backup
> > NAS (not running Ubuntu) and two or three desktop machines (some of
> > which, being laptops, come and go).
> > 
> > All mail from anwhere on the LAN is identified as being from the domain
> > zbmc.eu because it's behind a NAT router and that's the domain name as
> > seen from outside.
> > 
> > Messages to root, postmaster and other 'system' addresses on all the
> > machines are sent to me (chris at zbmc.eu) via settings in the /etc/aliases
> > file on each machine.
> > 
> > So far so good, it all works OK but there is one problem, it's not
> > always clear where a status/error mail message has come from because the
> > original addressee (root at serverx for example) is changed to
> > chris at zbmc.eu by the aliasing.
> > 
> > Can anyone suggest a way around this problem?
> > 
> > -- 
> > Chris Green
> > 
> 
> Have you considered aliasing to addresses like root_serverx at zbmc.eu then
> configuring your mail system to forward them to you so the mail headers
> will show you where they came from?
> 
That means setting up mailboxes for root_serverx at zbmc.eu and so on, then
forwarding them on to me but I guess it will work.  I'll do some
playing.

Obviously simply forwarding from root_serverx at zbmc.eu to chris at zbmc.eu
using the aliases file ends up with the problem I already have, there's
no obvious trace of root_serverx at zbmc.eu left in the normally viewed
mail headers (OK, I can look at the full headers and see where it came
from but that's a bit of a pain).

I think I'd have to set up an actual destination for each server to send
to (i.e. an account on my system, or a mailbox at my ISP) to get to see
the root_serverx at zbmc.eu destination as the To: address.

-- 
Chris Green