WHOIS

WHOIS is the text protocol that returned domain registration details for forty years. A client opened TCP port 43, sent a domain name and a newline, and read back whatever text the registry chose to send.

The format was never standardized. Field names, date formats and line ordering differed per registry, so every WHOIS parser is a pile of special cases, and the ones that get the creation date wrong get it wrong quietly.

What replaced it, and when

RDAP did, and the switch is largely done for generic top-level domains. ICANN set 2025-01-28 as the date its contracts stopped requiring WHOIS service for gTLDs, and registries turned it off in numbers through that year.

The traffic shows the same crossover. APNIC measured WHOIS queries falling from around 122 billion a month in January 2025 to about 49 billion by August, while RDAP rose from about 7 billion to about 65 billion. The two lines crossed in June 2025.

What Domduck records

Nothing through WHOIS. Every registration reading comes from RDAP, and there is no port 43 fallback.

The reason is data quality rather than fashion. A field read from a JSON document with a schema is either present or absent. A field scraped from free text is present, absent, or silently the wrong line, and the third case is indistinguishable from the first until somebody notices the dates are strange.

Why it matters

If you maintain a script that shells out to whois, it is on a clock. The usual failure is not an error, it is an empty or thin answer from a registry that now serves the real record over RDAP only.

Privacy redaction is separate from the protocol change and applies to both. Registrant contact details have been redacted by default since 2018 in most of the world, so neither protocol gives you a name and an email any more.