How to create a DMARC record? Print

  • DMARC, SPAM
  • 47

How to create a DMARC record? Once SFP and DKIM are in place, you configure DMARC by adding policies to your domain’s DNS records in the form of TXT records (just like with SPF or DKIM).

The TXT record name should be “_dmarc.your-domain.com.” where “yourdomain.com” is replaced with your actual domain name (or subdomain).

Here are common tags used in DMARC TXT records:

Tag name Required Purpose Sample
v required Protocol version v=DMARC1
p required Policy for domain p=quarantine
sp optional Requested handling policy for subdomains sp=reject
adkim optional Alignment mode for DKIM adkim=s
aspf optional Alignment mode for SPF aspf=r
pct optional % of messages subjected to filtering pct=20
ruf optional Addresses to which message-specific forensic information is to be reported (comma-separated plain-text list of URIs). ruf=mailto:[email protected]
rua optional Reporting URI of aggregate reports rua=mailto:[email protected]
fo optional Failure reporting format(s) fo=0
ri optional Aggregate Reporting interval ri=3600

Only the v (version) and p (policy) tags are required. Three possible policy settings, or message dispositions, are available:

  • none – Take no action. Log affected messages on the daily report only.
  • quarantine – Mark affected messages as spam.
  • reject – Cancel the message at the SMTP layer.

Alignment mode (aspf / adkim) refers to the precision with which sender records are compared to SPF and DKIM signatures, with the two possible values being relaxed or strict. represented by “r” and “s” respectively. In short, relaxed allows partial matches, such as subdomains of a given domain, while strict requires an exact match.


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