Summary

  • ARIN plans to retire the Whois-RWS API in July 2027 after resolving RDAP parity questions. One named gap is the old API's CIDR query for smaller registered blocks inside a larger one.
  • The Whois-RWS web interface has its own timetable: an Advanced RDAP Search beta will run in parallel for at least six months, with no web sunset date set.

When an address block is divided among customers, the parent record is only the cover of the book. The interesting names may be several pages down. ARIN's Whois-RWS API manual gives programs a /more query to retrieve narrower network registrations beneath a CIDR block. It also documents /less for the wider records above it. The new key has to open that drawer too.

At ARIN 58, ARIN identified this as the one detailed functional objection to retiring Whois-RWS. Its slides say RDAP does not yet expose the more-specifics result cleanly, and that hierarchy walking should be finished before RWS is switched off. That is unusually concrete feedback: a query, a missing answer and a sequence for fixing it.

The same roadmap puts the API sunset in July 2027, after the remaining parity questions and documentation work. ARIN's consultation result also promises training and outreach before deprecation. For the website at whois.arin.net, the path is different. ARIN is building Advanced RDAP Search, will run it beside the current interface for at least six months, and has left the web retirement date open.

That split matters to anyone maintaining a script. A new search page cannot repair a program that expects an API response listing the smaller blocks. ARIN has a good, testable promise now: show how an RDAP client gets the same nested registrations, document the call, then turn off the old endpoint. The calendar can wait for the answer sheet.