What is DMARC?
DMARC (Domain-based Message Authentication, Reporting, and Conformance) is an email authentication policy that tells receiving servers how to handle emails that fail SPF or DKIM checks.
DMARC (Domain-based Message Authentication, Reporting, and Conformance) builds on SPF and DKIM to give domain owners control over how receiving servers handle unauthenticated emails. It's the policy layer that ties your email authentication strategy together.
A DMARC record specifies three key things: what to do with emails that fail authentication (none, quarantine, or reject), where to send aggregate reports about email authentication results, and where to send forensic reports for individual failures. This gives you visibility into who is sending email on behalf of your domain.
DMARC also introduces the concept of alignment—the "From" domain in the email must match the domain used for SPF or DKIM authentication. This prevents attackers from passing SPF/DKIM with their own domain while spoofing yours in the visible "From" address.
Why DMARC Matters
DMARC gives you visibility and control over your email ecosystem. Without DMARC, you have no way to know if someone is spoofing your domain, and receiving servers have no guidance on how to handle suspicious emails. Major email providers increasingly require DMARC for bulk senders, and a strong DMARC policy significantly improves your deliverability and protects your brand.
How Ark Handles DMARC
Ark ensures all your emails pass DMARC alignment by properly configuring both SPF and DKIM for your sending domains. We recommend starting with a DMARC policy of 'none' to collect reports, then gradually moving to 'quarantine' and 'reject' as you verify all legitimate email sources are authenticated.
Frequently Asked Questions
What DMARC policy should I start with?
Start with p=none to monitor your email authentication without affecting delivery. Review the reports to identify all legitimate email sources, then gradually increase to p=quarantine and finally p=reject.
What do DMARC reports tell me?
DMARC aggregate reports show you which servers are sending email using your domain, whether those emails passed or failed authentication, and how receiving servers handled them. This helps you identify unauthorized senders and configuration issues.
How long does it take to implement DMARC?
You can add a basic DMARC record in minutes, but properly implementing DMARC—identifying all legitimate senders and moving to an enforcing policy—typically takes weeks to months depending on your email complexity.
Does DMARC affect email deliverability?
A properly configured DMARC policy improves deliverability by building trust with email providers. However, moving to an enforcing policy (quarantine or reject) before ensuring all legitimate emails pass authentication can cause delivery problems.
Related Terms
SPF
Sender Policy Framework (SPF) is an email authentication method that specifies which mail servers ar...
DKIM
DomainKeys Identified Mail (DKIM) is an email authentication method that uses cryptographic signatur...
Email Authentication
Email authentication is the process of verifying that an email was actually sent by the claimed send...
DNS Records
DNS records for email are entries in your domain's DNS that configure mail delivery (MX), sender aut...
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