Domain security
What is DMARC and why does it matter?
Short answer
DMARC is a DNS record that tells receiving mail servers what to do with email that claims to be from your domain but fails authentication: do nothing, send it to spam, or reject it. It also sends you reports. DMARC passes when SPF or DKIM passes and aligns with the visible From domain.
A DMARC record
_dmarc.example.com. TXT "v=DMARC1; p=none; rua=mailto:[email protected]"p=noneonly monitors.p=quarantinesends failures to spam.p=rejectblocks them.rua=is where daily aggregate reports are sent.sp=sets a different policy for subdomains.pct=applies the policy to a share of mail while you ramp up.
Alignment
It is not enough for SPF or DKIM to pass. The domain that passed must match the domain in the visible From address. That alignment is what stops someone else’s server from passing and still faking your From line.
Why it matters now
- It protects your customers and your brand from spoofed email.
- Since 2024, Google and Yahoo require bulk senders to publish DMARC, and mailbox providers increasingly favour authenticated mail.
- It is the only one of the three that gives you reports on who is sending as you.
How SageRank helps
The free report does not test domain security. SageRank’s Sentinel and Ultimate plans run ten levels of domain security checks through ShieldAI. See ShieldAI.