Updates to ARIN’s Registration RESTful Service (Reg-RWS)

Posted: Tuesday, 16 July 2019

On 2 December 2019, there will be two changes made to the RESTful API that ARIN uses for registration information. 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 https://www.arin.net/REST will be no longer be available for Reg-RWS. You must change your base URL to https://reg.arin.net to interface with ARIN’s Reg-RWS service. The reg.arin.net 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 https://datatracker.ietf.org/doc/draft-ietf-tls-oldversions-deprecate/ for further details.

We are providing you advance notice of these changes, as you may need to make configuration or code changes on your clients that interface with the Reg-RWS service. Both TLS 1.1 and TLS 1.2 are available now on reg.arin.net and we encourage you to make these changes so you will have no operational impact when we disable https://www.arin.net/REST 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)