ARIN's Whois-RWS Directory Service Available 17 July

Posted: Thursday, 15 July 2010

ARIN is pleased to announce that it will deploy its Whois-RWS service on 17 July 2010. We have corrected the issues that impacted the first release and are now able to bring you the following services that provide the general public with access to ARIN's registration data:

  • a RESTful Web Service (RWS)
  • a NICNAME/WHOIS port 43 service
  • a user-friendly web site (

When using the Whois-RWS you will notice some differences in behavior for certain queries and corresponding result sets on the NICNAME/WHOIS port 43 service. The detailed documentation on these differences has been updated and is now available at:

ARIN’s Directory Service for registration data has used the NICNAME/WHOIS protocol since its inception. The limitations of the NICNAME/WHOIS protocol are well known and documented in RFC3912. Whois-RWS was created as an alternative to the ARIN Whois and will provide much richer functionality and capability to the community.

ARIN continues to welcome community participation on the Whois-RWS mailing list, and we invite you to subscribe and share your experience and feedback about the new service:


Mark Kosters
Chief Technology Officer
American Registry for Internet Numbers (ARIN)