I am trying to send out mail with a proper message id (MID). I only use hostnames (host1, host2) and not (invalid) domains (host1.mydomain.net). The From line is okay because of a rewriting rule. I want Exim to appear as if it was running on host1.mydomain.net while it's actually running on host1. I have tried /etc/exim.conf and /etc/mailname to no avail. Is there an easy way to establish what I want? Bob