I've googled around a quite a bit and while I can find lots of instruction on what I need in order for Postfix to validate incoming mail, I find nothing about what I need to do to make sure Postfix does whatever it needs to do to make sure the MTA receiving the mail validates it. And the dearth of information in that category also begs the question, is there a special header that Postfix need to include in the message (as in DKIM) or do the receiving MTAs, if they're setup to use SPF just automatically do the DNS lookups? What is it, besides adding the correct the DNS TXT records, do I need to do on my end.
Thanks, Rob
