Email security tool

DMARC Checker

Look up the published DMARC record for a domain and understand its policy, reporting and enforcement.

What DMARC checks

DMARC is published as a TXT record at _dmarc.example.com. It tells receiving mail systems what to do when a message fails aligned SPF and DKIM checks, and where aggregate reports should be sent.

Understanding policy values

p=none monitors mail without requesting enforcement. p=quarantine asks receivers to treat failing messages as suspicious. p=reject requests that failing messages be rejected. Move toward enforcement only after reviewing reports and authorizing every legitimate sender.

DMARC is one part of email authentication

A strong deployment also needs correct SPF, valid DKIM signatures, identifier alignment, secure DNS access and ongoing report review. If you need implementation support, see my email and infrastructure services.

When to use the DMARC Checker

Use it when email from your domain lands in spam, before switching DMARC from p=none to quarantine or reject, or when checking a client's domain.

Examples

v=DMARC1; p=none; rua=mailto:dmarc@example.com monitors without blocking anything.
v=DMARC1; p=reject; adkim=s; aspf=s blocks mail that fails strict alignment.

Common mistakes

Publishing the record at the domain itself instead of at _dmarc.example.com.
Moving to p=reject before every sending service has working SPF or DKIM.

Created by Muhammad Irfan Aslam, Senior Systems & Cloud Engineer.