Ned Freed <ned.freed@xxxxxxxxxxx> wrote: > > > Wrong group of codes. Those are status for mail systems to return, not > > > the routing layer. > > > The point of null MX records it to explicitly say the address is invalid, > > so an address status would seem to make sense. > > No, the point is to say that a host is invalid. If you can't use them when the DNS says a mail domain is invalid then I don't understand if it ever makes sense to use 5.1.2 or 5.1.8. Tony. -- f.anthony.n.finch <dot@xxxxxxxx> http://dotat.at/ South-east Iceland: Southeasterly 4 or 5. Moderate. Occasional rain. Good, occasionally poor.