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by jeroenhd 27 days ago
> Why didn’t the DMARC spec say that a domain is “not present” if it lacks MX records?

MX implies a domain can receive email, you don't need it to send email. A setup where company.example sends email from companymailings.example but sets a reply-to for support@company.example is perfectly valid (even if it's stupid and confusing). Plus there's that weird legacy behaviour of mail servers delivering to port 25 to the IP in the A record if MX records are missing.
1 comments
amluto 27 days ago
> A setup where company.example sends email from companymailings.example but sets a reply-to for support@company.example is perfectly valid

So shouldn’t this be done explicitly by setting a policy at _dmarc.companymailings.example instead of implicitly by setting at otherwise entirely useless record (of type A? some unused TXT variant?) at companymailings.example?

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2000UltraDeluxe 26 days ago
No.

MX tells a sender where the mail goes.

DMARC allows the recipient to verify the adress in the From header.

Neither has anything to do with the fact whether a server sends emails or not.

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