Reminder--Upcoming Security Improvements for Whois-RWS, RDAP, and

Posted: Monday, 21 December 2020

Reminder: This previously-announced change is scheduled to be completed on or around 19 February 2021. Following is the original announcement:

Earlier this year, ARIN implemented security enhancements that included ending support for TLS 1.0 for Whois-RWS and RDAP services and improving ciphers used in As part of our continuing effort to improve security, on or around 19 February 2021, we will end support for TLS 1.1 and weak Diffie-Hellman (DH) key exchange parameters on, Whois-RWS, and RDAP. We will also update the ciphers available on Whois-RWS and RDAP to match those on www and The removal of TLS 1.1 may impact the way you interface programmatically with ARIN to query and retrieve information from Whois-RWS and RDAP.

Changes in our supported versions of TLS are due to well-known security issues with this protocol. More information is available at ARIN continues to support TLS 1.2. The cipher update satisfies ACSP Suggestion 2015.15: Improvements to SSL Security for

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 Whois-RWS and RDAP services. We encourage you to make these changes so you will have no operational impact when we disable the vulnerable transport protocol version.


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