[Exim] Central mailserver and same domain on all hosts

Setup: Exim 3.35 on fw that acts as central mailserver. Internal hosts send
everything to this one, running Exim 4.20. Want to use same domain name on
all hosts so filtering would be easier, i.e don't want to have to add a
condition for every host to get, say, cron-jobs into same maildir.
Problem: From mainlog.
remote host address is the local host: blacke.homelinux.net
postmaster@??? R=lookuphost defer (-1): remote host address
is the local host
Also got this in rewrite:
*@*.blacke.homelinux.net $1@???
Will be adding more hosts then it works.

What am I missing?