Daniel Lorch wrote:
Too complicated. I was thinking of a mailadress customers
would simply send a mail to and automagically parsing out
the headers with all mailservers.
That could be less simple than you like it to be: One of my
mail providers uses smtp.example as MSA, but then sends the
mail either via frontend1.example or via frontend2.example
You'd need the names resp. IPs of frontend1 and frontend2.
You could try to determine the domain and then look for an
existing sender policy for inclusion (include:example), and
if there is no policy you could guess whatever/24. But of
course this guess can be wrong. And it's definitely wrong
if your customer sends directly from a dyn. IP.
Bye, Frank