Public Interest Registry has introduced rate-limiting logic on the WHOIS Port 43 server and similar rate-limiting logic on the Public Interest Registry website.
Public Interest Registry monitors all IP addresses accessing the WHOIS Port 43 server. All traffic is logged, and rate-limit validation logic is applied to limit access by any given IP address. If a unique IP address exceeds the limit, the query will be stopped, and the error message will be displayed.
Users who submit queries to the public WHOIS port 43 are limited to 30 queries per minute. Public Interest Registry accredited registrars who submit queries through the WHOIS Port 43 search mechanism are limited to 50 queries per minute.