DMARC np — Non-existent subdomain policy
A policy specifically for subdomains that have no DNS records at all.
- Required
- no
- Default
- inherits sp, then p
- Valid values
none | quarantine | reject
What it does
Introduced in the DMARCbis revision. Attackers frequently spoof subdomains that were never provisioned, because those have no MX or A records and often escape notice. np=reject shuts that down without affecting real subdomains. Support is still uneven across receivers, so publish it as a supplement to sp rather than a replacement.
Example
v=DMARC1; p=reject; sp=reject; np=reject; rua=mailto:dmarc@example.com