postfix: mail forwarding for domain if user unknown

[Thomas Nintemann]

> If fact both kolab server are speaking together but they use some
> intermediate server(s) and
> also pop3 protocol (fetchmail)
Ok let's say that the ISP relay (smarthost) is in the middle of the two 
kolab-servers. The one kolab-system sends mail for users at example.com that 
have a fake (real ISP SMTP relay) kolabHomeServer to the ISP relay server and 
the other kolab-server get's the mail via fetchmail. 

> This is any SMTP server different of the kolab server itself that will
> accept to relay email to
> its final destination, where (the final destination) fetchmail of the
> other server will download them.
Ok, that is grasped.
> Usually your ISP provide you such kind of server.
I think so, but i will try...
>
> a "fake" kolab server, but a real SMTP server anyway !
>
Ok. nothing can be send out without real SMTP.
>
> Yes If the "fake" server you used is the same as the smarthost you
> have setup, but...
> Sorry for using the word smarthost that is already used in kolab GUI.
> For me smarthost means any SMTP server that will accept to relay all
> your emails using only DNS MX pointers for routing, without doing any
> filtering, address rewriting, or local delivery.
I hope my ISP Relay can do so. 
>
> > Then the other kolab-server get's the email for user2 at example.com with
> > fetchmail and deliver the mail for the real mailbox.
> >
> > Is that accurate? Please correct me if i think wrong...
>
> Yes

OK, thanks very much for you advertence to my problem with the "one domain on 
two kolab-systems without direcly connection".

On Friday i get a chance to test the scenario and i will post the outcomes 
here to the list.

Thomas