We have a domain that has been "ruined" by spammers, using it's reputation for sending spam mails.
We're moving to a different domain and would like the previous domain to become a "death trap"; marking any new mail using the domain for from:, replyto: or bounce: as spam.
Setting up DMARC and SPF to reject all emails is easy, but how will this affect emails already received? Are DMARC records ever re-checked after already having been checked once?
Email authentication is checked before the email arrives. I think this image maps it out well. I don't think you're in danger of having emails checked retroactively. Once an email has run the gauntlet, it's done.
Neil is correct, +1.
I just wanted to make you aware that SPF has nothing to do with the from:, reply-to: or bounce:. It focuses on the return-path:, which you might be referring to as the bounce:? DMARC applies to the from:.
So if someone uses the domain in reply-to: unfortunately their's nothing you can do about it.
If someone was able to spam through your old domain, they would be able to do it to the new domain, unless you were able to find the vulnerability and plug it.
