Fog user's hostname in the Message-ID
Created by: geistesk
The Message-ID
-field of an outgoing email contains the user's hostname, set by the email client. This hostname can reveal both the hostname (obvious) and furthermore the network's domain name. For example this field says if I am currently at home, at work, at the university and so on.
This PR intends to replaces the hostname part with the server's FQDN.