@lbutlr: > In short, does postfix need to know the name the client used to connect > to the server?
By default, Postfix does not care how a client discovers an MTA
(which MX record was used, if any, etc.).
You can configure postscreen to require that a client tries a
more-preferred MX before a less-preferred MX, but that is entirely
optional.
Wietse
