On Tue, Sep 02, 2014 at 06:44:19PM +0200, Robert Schetterer wrote: > so this stays as valid mx record ? > > $ dig -t mx airbus.com > airbus.com. IN MX 0 vip-smtp.airbus.gmessaging.net.
Yes, of course. > and this is what nullmx is done rightly? > > $ dig -t mx stoerseite.de > stoerseite.de. IN MX 0 . Yes, provided stoerseite.de neither receives nor sends (as envelope sender) any email. The "nor sends" part is a side-effect of many domains (including mine) refusing email from envelope senders in unreachable domains (reject_unknown_sender_domain). -- Viktor.