exim -> forwarding mail

[Graham Ashton <graham@mirror.bt.co.uk>]

I'm running exim on my mail server, which is fully DNS registered, and
has proper connectivity to the outside world. I'll call it

  server.domain1.com

One of my mates wants me to set it up so that mail sent to
user@domain1.com gets directed to his workstation (which doesn't have an
MX record), which I'll call

  workstation.domain2.com

I'm sure it's possible to get this stuff to work, but I'm getting a
little confused by all the router, director and transport terminology in
the manual.

I've entered an alias in /etc/aliases as follows;

  user: user@workstation.domain2.com

but when I send a message to user@domain1.com it bounces, with the
following error:

--cut--
A message that you sent could not be delivered to all of its recipients.
The following address(es) failed:

  user@workstation.domain2.com:
    (generated from user@domain1.com):
    unrouteable mail domain "workstation.domain2.com" 
--cut--

I've checked that his machine is capable of accepting mail by telnetting
to port 25 and using the "VRFY user@workstation.domain2.com" command.

What would be the easiest safe way of getting this working (without
getting him an MX entry, which is frowned upon round here for people's
desktop machines).

Any advice would be much appreciated.

I noticed the ROUTERS CONFIGURATION section in /etc/exim.conf. Is this
the right place to be looking? Should I put the;

  literal:
    driver = ipliteral
    transport = remote_smtp

section before the

  lookuphost:
    driver = lookuphost
    transport = remote_smtp

section? Is that the best solution? I'd rather do something like that on
a host by host basis if possible, which is a bit beyond me.

Thanks.

P.S. I'm running the latest version of slink.

-- 
Graham