Reminder: Changes to Reg-RWS scheduled for 2 December

Posted: Wednesday, 30 October 2019

As we originally announced on 16 July 2019, ARIN will implement changes to its RESTful API on 2 December 2019. These changes may impact the way you interface with ARIN Online for sending reassignment information and receiving reports through ARIN’s Registration RESTful Service (Reg-RWS). The changes are:

  1. The base URL will be no longer be available for Reg-RWS. You must change your base URL to to interface with ARIN’s Reg-RWS service. The service has been available for over seven years.
  2. ARIN will no longer be supporting TLS 1.0 for Reg-RWS’s transport layer. There are well-known security issues with this protocol. We will continue to support TLS 1.1 and 1.2. Please make sure your client implementation will support TLS 1.1 or 1.2. Read for further details.

Because these changes will be implemented in about 30 days, we recommend that you review your clients that interface with the Reg-RWS service and make any required configuration or code changes now. Both TLS 1.1 and TLS 1.2 are available now on and we encourage you to make these changes so you will have no operational impact when we disable and the vulnerable transport protocols.

So that you can plan your upgrades accordingly, we would also like to inform you of future planned events for this service. We will be adding TLS 1.3 support to Reg-RWS in the near future. We also anticipate announcing end-of-service support for TLS 1.1, with another corresponding 120 day warning notice.


Mark Kosters
Chief Technology Officer

American Registry for Internet Numbers (ARIN)