Mail exchange record
Provide a mail exchange record pointing to mx1.hdm-stuttgart.de. Test this configuration using dig accordingly.
Caveat: Configuring a client machine using your name server and
sending a mail to xy123@mi.hdm-stuttgart.de won't work
since the HdM's mail filters will deliver these mails to the MI mail
server mail.mi.hdm-stuttgart.de rather than to
mail.hdm-stuttgart.de (and you probably have no account on
this particular machine). In addition both servers will reject mails
having destination addresses differing from
...@hdm-stuttgart.de or
...@mi.hdm-stuttgart.de respectively.
