Email & SMTP · 1 min read
Email Authentication: DMARC
What DMARC is
DMARC (Domain-based Message Authentication, Reporting and Conformance) builds on SPF and DKIM. It tells receiving servers what to do when an email claiming to be from your domain fails those checks, and sends you reports about it. Gmail and Yahoo require DMARC for bulk senders.
Policies
p=none: monitor only. Mail is delivered normally while you collect reports.p=quarantine: send failing mail to spam.p=reject: block failing mail. This is the end goal once all your legitimate mail passes.
Add a DMARC record
- Sign in to your DNS provider.
- Add a TXT record with host
_dmarc(so it becomes_dmarc.yourdomain.com). - Enter a value such as:
v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com - Save and wait for DNS to update (up to 48 hours).
Tips
- Have only one DMARC record per domain.
- Start at
p=none, review your reports, then move toquarantineandreject. - Make sure every service that sends email for you (including FunnelStreams) is set up with SPF and DKIM before you tighten the policy.
Using a shared sending domain
If you send from a free or shared address and see DMARC failures, set up a dedicated sending domain and send from your own domain.