[Dovecot] How do folk . . . Aggregate system mail from LAN machines?

[Ron Leach]

List, good evening,

Running Dovecot for external email, but not yet worked out how (best) 
to aggregate 'system' mail from other machines on the LAN.  By system 
mail, I mean mails generated by the OS or by applications, and 
addressed to root, or 'some admin user', etc.  Ideally, these would be 
seen by 'root' or 'some admin user' or whoever on our existing 
Dovecot/IMAP system.  Our scale is not large, we only have 5 servers 
on the LAN doing various things.

I wondered how other Dovecot users do this.  I've thought of 3 
possibilities:

1.  Install Dovecot on each LAN machine, and use Fetchmail to retrieve 
the messages using POP so that local mail stores were emptied.

2.  Perhaps, use a 'forwarding' mechanism of some sort on each LAN 
machine, but that would require an MTA on each LAN machine, would it not?

3.  I wondered whether /etc/alias, mentioned in a recent post by 
Simone Caruso, might help though again, presumably, requiring an MTA 
on each LAN machine.

What do you do?

regards, Ron