Authentication
What is Domain-based Message Authentication, Reporting and Conformance (DMARC)?
A policy layer built on SPF and DKIM that tells receivers how to handle mail that fails authentication and where to send reports.
DMARC is published as a DNS TXT record at _dmarc.yourdomain.com and ties SPF and DKIM together through alignment with the visible From domain. It specifies a policy of none, quarantine, or reject for messages that fail authentication and requests aggregate and forensic reports. A message passes DMARC when either SPF or DKIM passes and is aligned with the From header domain.
Why it matters for cold email
Since 2024, Google and Yahoo require a DMARC record for bulk senders, so cold email at scale must have at least a p=none policy in place. DMARC aggregate reports also expose spoofing and misconfigured sending sources before they damage your domain reputation.
Related terms
Stop guessing at deliverability.
Scheduler Zero handles authentication, warmup, and sender reputation so your cold email lands in the inbox, not the spam folder.