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Security, Stability, and Resiliency Review (SSR)

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SSR2 Review Workspace Landing Page
Find the latest status updates, recordings of past meetings, and opportunities to participate
Introduction to Reviews
Learn more about Reviews, their purpose and process for conducting and opportunities to participate
SSR2 Review Meeting Schedule
Find the schedule to observe SSR2 Review Team Meetings
SSR2 Fact Sheet
See the progress of the SSR2 Review Team towards completing the Review
Implementation Progress
See progress of implementation of Recommendations from past Reviews

Objectives of the SSR Review

Under the Bylaws (Section 4.6(c)), ‘The Board shall cause a periodic review of ICANN’s execution of its commitment to enhance the operational stability, reliability, resiliency, security, and global interoperability of the systems and processes, both internal and external, that directly affect and/or are affected by the Internet’s system of unique identifiers that ICANN coordinates (“SSR Review”).’

The issues that the review team for the SSR Review (“SSR Review Team”) may assess are the following:

  1. security, operational stability and resiliency matters, both physical and network, relating to the coordination of the Internet’s system of unique identifiers;
  2. conformance with appropriate security contingency planning framework for the Internet’s system of unique identifiers;
  3. maintaining clear and globally interoperable security processes for those portions of the Internet’s system of unique identifiers that ICANN coordinates.

The SSR Review Team shall also assess the extent to which ICANN has successfully implemented its security efforts, the effectiveness of the security efforts to deal with actual and potential challenges and threats to the security and stability of the DNS, and the extent to which the security efforts are sufficiently robust to meet future challenges and threats to the security, stability, and resiliency of the DNS, consistent with ICANN’s Mission.

The SSR Review Team shall also assess the extent to which prior SSR Review recommendations have been implemented and the extent to which implementation of such recommendations has resulted in the intended effect.

The SSR Review shall be conducted no less frequently than every five years, measured from the date the previous SSR Review Team was convened (see Bylaws, Section 4.6(c)).

Review Progress and Milestones

​Watch a brief video by ICANN's CTO, as he discusses the 2nd Security, Stability, and Resiliency of the DNS Review Team.

The graphic below illustrates phases and status of each review - a  indicates that all activities within a given phase have been completed.  The chart that follows the graphic provides further details of key activities and milestones within each phase – you can view these details by clicking on each of the phases in the graphic.  The table also contains links to relevant documents.

PhaseActivityDescriptionStart DateDocuments
Assemble Review TeamCall for VolunteersPublic announcement inviting volunteers to submit application30 Jun 2016
Call for Volunteers ExtensionApplication Extended for the Second Security, Stability and Resiliency (SSR-2) Review Team12 Aug 2016
Review Team AnnouncedSelection of the Second Security, Stability, and Resiliency of the DNS Review Team Members Announced14 Feb 2017
Appointment of Board DesigneeBoard appoints a member to the Second SSR Review Team3 Feb 2017
Plan ReviewVariousReview team activities and detailed information available on the community wiki30 Jun 2016
Conduct ReviewSecond Security, Stability, and Resiliency of the DNS Review (SSR2) RestartsThe Second Review of the Security, Stability, and Resiliency of the Domain Name System (SSR2) formally restarted 07 June 2018. 7 Jun 2018
Additional FundingBoard resolution approving additional funding7 Nov 2019
Draft ReportDraft Report for Public Comment24 Jan 2020
Public Comment on Draft ReportPublic comment on Second Security, Stability and Resiliency (SSR2) Review Team Draft Report24 Jan 2020
Public Comment ExtendedPublic Comment Period Extended: SSR2 Review Team Draft Report3 Mar 2020
Final Report Executive SummaryExecutive summary of the SSR2 Final Report22 Jan 2021
Final ReportSecond Security, Stability, and Resiliency (SSR2) Review Team Final Report25 Jan 2021
Board ActionPublic Comment on Final ReportFinal report and recommendations posted for Public Comment28 Jan 2021
Board receipt of the Final ReportBoard receipt of the Final Report3 Mar 2021
Board Action on RecommendationsBoard resolution taking action on 63 recommendations22 Jul 2021
Rationale supporting Board resolutionRationale supporting Board resolution22 Jul 2021
ScorecardScorecard: Final SSR2 Review Team Recommendations22 Jul 2021
Board BlogBoard Action and Next Steps on the SSR2 Review26 Jul 2021


Domain Name System
Internationalized Domain Name ,IDN,"IDNs are domain names that include characters used in the local representation of languages that are not written with the twenty-six letters of the basic Latin alphabet ""a-z"". An IDN can contain Latin letters with diacritical marks, as required by many European languages, or may consist of characters from non-Latin scripts such as Arabic or Chinese. Many languages also use other types of digits than the European ""0-9"". The basic Latin alphabet together with the European-Arabic digits are, for the purpose of domain names, termed ""ASCII characters"" (ASCII = American Standard Code for Information Interchange). These are also included in the broader range of ""Unicode characters"" that provides the basis for IDNs. The ""hostname rule"" requires that all domain names of the type under consideration here are stored in the DNS using only the ASCII characters listed above, with the one further addition of the hyphen ""-"". The Unicode form of an IDN therefore requires special encoding before it is entered into the DNS. The following terminology is used when distinguishing between these forms: A domain name consists of a series of ""labels"" (separated by ""dots""). The ASCII form of an IDN label is termed an ""A-label"". All operations defined in the DNS protocol use A-labels exclusively. The Unicode form, which a user expects to be displayed, is termed a ""U-label"". The difference may be illustrated with the Hindi word for ""test"" — परीका — appearing here as a U-label would (in the Devanagari script). A special form of ""ASCII compatible encoding"" (abbreviated ACE) is applied to this to produce the corresponding A-label: xn--11b5bs1di. A domain name that only includes ASCII letters, digits, and hyphens is termed an ""LDH label"". Although the definitions of A-labels and LDH-labels overlap, a name consisting exclusively of LDH labels, such as"""" is not an IDN."