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.
Importance
Optional
Optional
Tag
psd=
Default
n
n
Example
psd=n
✅ Valid Values
y
This is a Public Suffix Domain. Its direct subdomains are organisational domains.
n
Not a Public Suffix Domain (default for normal registered domains).
💬 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.
📚 RFC References
🔗 Related DMARC Tags
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