ICANN Announcements

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Root Stability Study Final Report Now Available

8 March 2017

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LOS ANGELES – 8 March 2017 – The Internet Corporation for Assigned Names and Numbers (ICANN) today published the final report regarding the Continuous Data-Driven Analysis of Root Server System Stability (CDAR). The study examines the New gTLD Program's technical impact of the delegation of new gTLDs on the security and stability of the root Domain Name System (DNS) and is informed by publicly available, historical measurement data.

Read the report [PDF, 3.49 MB].

The CDAR study was conducted by independent research organization TNO and its consortium partners, SIDN and NLnet Labs. The findings will help the ICANN community going forward to determine if any additional steps are necessary if more TLDs are to be added the root zone system.

A draft report was published for comment on 27 October 2016. The revised, final version available today incorporates suggestions received during the public comment period. The revisions include additional discussion regarding the data used and recommendations presented in the original report. Additionally, some of the presented analysis results in the draft report are updated based on data that became available after the publication of the draft report. The report of public comments [PDF, 520 KB], which includes summary and analysis of the comments received regarding the study's findings, was published on 9 February 2017.

ICANN commissioned this study in response to a recommendation from the Governmental Advisory Committee (GAC) to examine the technical impact of the delegation of new gTLDs on the security or stability of the root DNS system. The final report is expected to serve as input for community discussions regarding the future expansion of the root zone. The findings and recommendations will also be presented to the ICANN Board for consideration.

New gTLD Program Reviews

ICANN's New gTLD Program has enabled hundreds of new top-level domains to enter into the Internet's root zone since the first delegations occurred in October 2013. The CDAR study is part of a series of comprehensive reviews of the program that are currently underway in a number of areas, including competition, consumer trust and choice, security and stability, rights protection and other areas.


ICANN's mission is to help ensure a stable, secure and unified global Internet. To reach another person on the Internet, you have to type an address into your computer - a name or a number. That address has to be unique so computers know where to find each other. ICANN helps coordinate and support these unique identifiers across the world. ICANN was formed in 1998 as a not-for-profit public-benefit corporation and a community with participants from all over the world. ICANN and its community help keep the Internet secure, stable and interoperable. It also promotes competition and develops policy for the top-level of the Internet's naming system and facilitates the use of other unique Internet identifiers. For more information please visit: www.icann.org.