On Fri, Jan 01, 2021 at 04:50:16PM -0700, Bob Proulx wrote: > > SPF identifies authorized IP addresses for domains in the message > envelope. Therefore the reverse DNS pointer record does not matter in > this. The hostname does not matter. Only the IP address as indicated > through a DNS response. This is an anti-forgery protection. This has > been a defacto standard requirement for all SMTP host sites for some > years now. Must have valid SPF records. However I do know of small > low activity sites that still do not implement this and squeeze by > depending upon the nebulous value of the sending host's "IP reputation > score". >
I used to be postmaster for a large organisation and know for a fact that even if you have SPF and DKIM set up properly there are still places on the internet that will insist on the forward/reverse check and reject the mail if the addresses don't match. I can't give specific examples, I cannot remember, but they exist so keep an eye out for rejected mails. -- Brett Lymn -- Sent from my NetBSD device. "We are were wolves", "You mean werewolves?", "No we were wolves, now we are something else entirely", "Oh"
