DMARC psd= Tag: Public Suffix Domain (psd)
The DMARC psd tag (RFC 9989) indicates whether the domain is a Public Suffix Domain. Relevant for domain registries and operators of top-level or shared domains.
Published · Last verified · Maintained by TamingDNS
Optional
psd=
u (unknown)
psd=n
✅ Valid Values
y
This is a Public Suffix Domain. Its direct subdomains are organisational domains.
n
Not a Public Suffix Domain, and this domain is the organisational domain for itself and its subdomains.
u
The default. Not a PSD, and it may or may not be an organisational domain, so receivers run the RFC 9989 §4.10 tree walk to find out.
💬 What This Tag Does
Added in RFC 9989 (DMARCbis), the "psd" tag marks whether a domain is a Public Suffix Domain (like a TLD or shared hosting domain). This is almost never relevant to ordinary domain owners. It's designed for domain registries and operators of shared domain spaces. Setting psd=y tells receivers that the domain's subdomains should each be treated as their own organisational domain.
📋 Complete Example Records
Every one of these is a complete record you can paste as it stands. Each goes in a TXT record at
_dmarc.yourdomain.com. Check yours with the
DMARC Checker
or assemble one in the
DMARC Builder.
v=DMARC1; p=reject; sp=none; np=reject; psd=y; rua=mailto:dmarcrpts@fTLD.com,mailto:04bd0f9f9f@rua.easydmarc.us
The .bank top-level domain's own record. This is what psd=y is for, and almost nobody reading this needs to publish it.
v=DMARC1; p=reject; rua=mailto:dmarc-feedback@example.com
With no "psd" tag the default "u" applies. Receivers run the tree walk to work out the organisational domain, which is the right answer for an ordinary domain.
v=DMARC1; p=reject; psd=n; rua=mailto:dmarc-feedback@example.com
This claims more than leaving the tag out. "n" asserts the domain is not a PSD and is the organisational domain for itself and its subdomains.
📚 RFC References
🔗 Related DMARC Tags
🛡️ Related Tools
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