Internet Corporation for Assigned Names and Numbers

Name Collision Resources & Information

Resources for IT Professionals

The following materials have been created to give IT Professionals the tools needed to understand and address the root cause of name collision.

Name Collision Overview

A name collision occurs when an attempt to resolve a name used in a private name space (e.g. under a non-delegated Top-Level Domain, or a short, unqualified name) results in a query to the public Domain Name System (DNS). When the administrative boundaries of private and public namespaces overlap, name resolution may yield unintended or harmful results.

Name collisions are not new. The introduction of any new Domain Name into the DNS, whether a generic TLD, country code TLD or Second-Level Domain name creates the potential for name collision. ICANN's New gTLD Program has renewed public interest in the issue, as concerns have been raised about the increase in domain names leading to an increase in potential collisions. A secure, stable and resilient Internet is ICANN's number one priority. Therefore, we've made a commitment to the Internet community to launch a substantial effort to mitigate and manage collision occurrence.

ICANN's Role in Addressing Name Collision

It is unlikely that domain name collisions will affect significant numbers of corporate network operators or Internet users. However, ICANN considers it essential that it does everything possible to minimize potential impact and to offer clear advice on dealing with the issue.

In May 2013, ICANN commissioned a study [PDF, 3.34 MB] to explore the scope and risk of name collision in relation to new gTLDs. A series of proposals and public comment periods followed, resulting in the New gTLD Collision Occurrence Management Plan [PDF, 841 KB]. On 11 November 2013, ICANN announced the selection of a lead for creating a "Name Collision Occurrence Management Framework," in cooperation with the community. A historical record demonstrating how the multistakeholder process helped ICANN arrive at a better, more thorough solution for addressing name collision can be found in the News Archive section of this page (below). Part of the solution is to provide educational outreach to those who may be affected by collision, and the Resources section (above) supports that goal.

News Archive

Announcement: Independent Report Maps Possible Way Forward in Mitigating Domain Name Collisions
Publish Date: 26 February 2014
An independent report commissioned by ICANN, Mitigating the Risk of DNS Namespace Collisions, has offered a set of concrete recommendations on how to mitigate potential risks of domain name collisions.

Announcement: New gTLD Collision Occurrence Management Plan Frequently Asked Questions
Publish Date: 3 December 2013
ICANN provides the most sought-after information regarding name collision occurrence.

Meeting Content: Name Collision Update at ICANN 48 in Buenos Aires
Publish Date: 19 November 2013
A session that allow chart the way forward on Name Collision.

Meeting Content: Security and Stability Update at ICANN 48 in Buenos Aires
Publish Date: 18 November 2013
An open community session wherein the Security Team presented and opened discussion on the latest developments regarding Security, Stability, and Resiliency in regard to new gTLDs.

Announcement: ICANN Selects Lead for Development of Name Collision
Publish Date: 11 November 2013
ICANN signed an agreement with JAS Global Advisors LLC to lead the development of the Name Collision Occurrence Management Framework, in cooperation with the community.

Document: AC062 SSAC Advisory Concerning the Mitigation of Name Collision Risk [PDF, 382 KB]
Publish Date: 7 November 2013
An Advisory to the ICANN Board from the Security and Stability Advisory Committee (SSAC) concerning ICANN's proposal to mitigate name collision risks.

Questions & Answers: New gTLD Applicant Update Webinar – 23 October 2013 [PDF, 223 KB]
Publish Date: 23 October 2013
Answers to questions about Name Collision raised by New gTLD Webinar participants.

Blog Post: How the 2013.10.07 NGPC Resolution on Name Collision Affects the New gTLD Program Contracting Process
Publish Date: 20 October 2013
After several months of work including input from numerous members of the ICANN community, the New gTLD Program Committee (NGPC) has taken action on two key issues affecting applicants of the program – GAC Category 2 Advice and Name Collision.

Announcement: NGPC Resolution on Name Collision Requires Registry Agreement Update
Publish Date: 16 October 2013
The adoption of the 2013.10.07 resolution by the New gTLD Program Committee of the ICANN Board cleared the way for new gTLDs to move forward to Delegation, while addressing concerns about Name Collision raised by the community. In order to comply with the NGPC's Resolution, ICANN made a "Required Change" to Specification 6 of the Registry Agreement for new gTLDs.

Blog Post: Moving Forward with Delegation of Top-Level Domains
Publish Date: 9 October 2013
ICANN's New gTLD Program Committee (NGPC) has approved resolutions allowing us to move forward in expanding the Internet's name space while mitigating possible issues in the expansion.

Document: New gTLD Collision Occurrence Management [PDF, 841 KB]
Publish Date: 7 October 2013
ICANN staff created a proposal to manage collision occurrences between new gTLDs and existing private uses of the same strings. This proposal was approved by the NGPC.

Statement: ALAC Welcomes Proposal to Mitigate Name Collision
Publish Date: 27 August 2013
The ALAC welcomes the completion and publication of the "Name Collisions in the DNS" study report by Interisle Consulting Group and the subsequent response by ICANN in "New gTLD Collision Risk Management Proposal.

Board Resolutions: New gTLD Collision Occurrence Management Program
Publish Date: 7 August 2013
The New gTLD Program Committee (NGPC) of the ICANN Board approved resolutions directing ICANN staff to manage the occurrence of collisions between new gTLDs and existing private uses of the same strings, and enact the proposed name collision outreach campaign.

Public Comment: Proposal to Mitigate Name Collision Risks
Publish Date: 5 August 2013
Purpose: To solicit community comment on proposed efforts to mitigate potential impact resulting from name collisions as New gTLDs are delegated into the root zone.

Document: New gTLD Collision Risk Mitigation [PDF, 166 KB]
Publish Date: 5 August 2013
Proposal to manage the collision occurrences between new gTLDs and existing private uses of the same strings.

Announcement: Addressing the Consequences of Name Collisions
Publish Date: 5 August 2013
As directed by the ICANN Board of Directors on 18 May 2013, ICANN commissioned and released the results of a study that considers the likelihood and impact of name space collisions between applied-for newgTLD strings and non-delegated TLDs.

Study: Name Collision in the DNS [PDF, 3.34 MB]
Publish Date: 2 August 2013
A study of the likelihood and potential consequences of collision between new public gTLD labels and existing private uses of the same strings. Performed by third party researcher, Interisle.

Meeting Content: Security, Stability & Resiliency Update at ICANN 47 Durban
Publish Date: 17 July 2013
A community session intended to discuss security and stability topics and shed light on the study on name collision.

Board Resolution: SSAC Advisory on Internal Name Certificates
Publish Date: 18 May 2013
The ICANN Board of Directors directs staff, in consultation with the ICANN Security and Stability Advisory Committee (SSAC), to commission a study on the use of TLDs that are not currently delegated at the root level of the public DNS in enterprises, which considers the potential security impacts of applied-for new-gTLD strings in relation to this usage.

Report: SAC 045 – Invalid Top Level Domain Queries at the Root Level [PDF, 507 KB]
Publish Date: 15 November 2010
The ICANN Security and Stability Advisory Committee (SSAC) calls attention to the potential problems that may arise name collision in this report, which was published for community and Board review.

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