No. DMARC is about if the from address has to match the address used in dkim/spf
DMARC is primarily about "alignment" (switching SPF from caring about the envelope sender to instead using the from header). Yes, it does also tangentially address those other points, but the primary reason it was adopted was to prevent spoofing of from headers (where in original spf that was a non-goal)
Back then, I didn’t use Terraform or anything like that, but I had text files with logs that described the DNS setup in detail so I could fix things. By grepping through the logs, I’m able to put a definitive bound on when I added DMARC—it was no later than June 2016, over 10 years ago.
At the time I thought, “Obviously, we should all be setting this up, because recipients will start rejecting mail from insecure domains, if they don’t already.”
>But for small personal domains the value isn't that high.
I don't understand the resistance. It benefits the entire mail ecosystem, not just mass senders.
SPF used to be niche thing, then everyone realised it's a good idea and it became more-or-less mandatory. Same with DKIM. Now it has happened to DMARC as well.
Is there a risk some people on this thread are mixing up DKIM and DMARC?
DKIM = proving that an email was sent from a specific domain using cryptography. Good for spam fighting and deliverability.
DMARC = telling receivers how to handle mail that fails authentication.
DMARC is primarily useful for large, complex organizations where email admins may not be aware of everyone inside the org who is sending mail that advertises the domain in the From header, or organizations that might be targeted by impersonation attacks (e.g. phishing). Being able to tell recipients "yes we absolutely have our act together so feel free to reject or spamfolder unauthenticated email" is great for killing phishing campaigns, and being able to request reports is great for finding that one sales org that signed up for a guerrilla marketing SaaS that's impersonating them.
But for small personal domains the value isn't that high.