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.internal

For the broader context, see Private Use TLD and Special-Use Domain Names.

.internal is a top-level label reserved by ICANN for private-use DNS namespaces that are not part of the global public DNS root. In July 2024, the ICANN Board resolved that .internal will never be delegated in the root zone, so that it can be used by organisations as a non-colliding private-use TLD.[1][2]

Background and SAC113[edit | edit source]

The reservation of .internal implements a long-standing recommendation from ICANN’s SSAC. SAC113 (SSAC Advisory on Private-Use TLDs) documented widespread ad hoc use of private TLDs such as .corp, .home and .mail, and the resulting leakage of queries into the public DNS.[3] To reduce name collision risk, SAC113 recommended that the ICANN Board ensure a single DNS label be identified and reserved at the top level for private use, and that this label must never be delegated in the root zone.[3]

In response, ICANN developed a procedure for selecting such a label and asked IANA to evaluate candidate strings against criteria derived from SAC113: the label had to be a valid DNS name, undelegated, not confusingly similar to existing TLDs, and relatively short, memorable and meaningful.[4] Community input via public comment and advice from advisory committees (including SSAC and ALAC) supported the selection of .internal for this role.[5][6]

Selection and Reservation[edit | edit source]

On 24 January 2024, IANA announced a provisional determination that .internal was the preferred candidate for a private-use TLD and opened a public comment period on this choice.[7] IANA’s assessment compared several possible strings and concluded that only .internal and .PRIVATE broadly met the selection criteria, with .internal ultimately recommended as clearer and less ambiguous across languages.[4][8]

Following review of public comments and technical input, the ICANN Board adopted Resolution "2024.07.29.06", which permanently reserves .internal from delegation in the DNS root zone “to provide for its use in private-use applications”.[1][9] The Board noted that this action is not expected to introduce new security or stability issues, and asked ICANN org to raise awareness of the reservation through technical outreach.[1][2]

Intended Use and Relationship to Other Namespaces[edit | edit source]

The .internal label is intended as a top-level domain for private DNS namespaces resolved only within closed networks, in contrast to special-use names such as .local and .alt that are defined in IETF RFCs and handled by specific resolution mechanisms.[10][11] An IETF Internet-Draft describing .internal explains that organisations needing a private-use DNS namespace should either use subdomains of a globally delegated name under their control or use .internal, and stresses that names under .internal are resolved using the DNS protocol but are not meant to appear in the global DNS or the root zone.[10]

Unlike .local or .home.arpa, .internal is not registered as a Special-Use Domain Name under RFC 6761, and no special resolution behaviour is defined beyond the prohibition on root-zone delegation. It is therefore closer to a policy-reserved label, analogous in spirit to private-use IP address ranges described in RFC 1918 and the shared-address space in RFC 6598, but applied to the DNS namespace.[3][12]

From a governance perspective, .internal is one element in a broader set of measures that aim to give private and alternative namespaces clearer boundaries while preserving a single, coherent public DNS root.[13][14]

See Also[edit | edit source]

References[edit | edit source]

  1. ↑ 1.0 1.1 1.2 ICANN Board, "Approved Resolutions – Special Meeting of the ICANN Board", 29 July 2024.
  2. ↑ 2.0 2.1 A. McConachie, "'.INTERNAL will never exist in the DNS root zone'", RIPE 89, October 2024.
  3. ↑ 3.0 3.1 3.2 ICANN SSAC, "SAC113: SSAC Advisory on Private-Use TLDs – Executive Summary", 18 September 2020.
  4. ↑ 4.0 4.1 IANA, "Identification of a Top-Level Domain for Private Use", 24 January 2024.
  5. ↑ ICANN, "Public Comment: Proposed Top-Level Domain String for Private Use", 24 January 2024.
  6. ↑ At-Large Advisory Committee, "Comment on Proposed Top-Level Domain String for Private Use", 21 March 2024.
  7. ↑ IANA, "Proposed Top-Level Domain String for Private Use", 24 January 2024.
  8. ↑ Digital Watch, "ICANN proposes reserving '.internal' as top-level domain for private-use applications", 30 January 2024.
  9. ↑ ICANN Board Technical Committee, "Activities Report January–June 2024", 30 June 2024.
  10. ↑ 10.0 10.1 K. Davies et al., "A Top-level Domain for Private Use", Internet-Draft draft-davies-internal-tld-04, 2 July 2025.
  11. ↑ P. Hoffman et al., "The .alt Special-Use Top-Level Domain", RFC 9476, IETF, September 2023.
  12. ↑ IANA, "IANA-managed Reserved Domains" (accessed 2025-12-11).
  13. ↑ ICANN SSAC, "SAC090: SSAC Advisory on the Stability of the Domain Namespace", December 2016.
  14. ↑ ICANN SSAC, "SAC123: SSAC Report on the Evolution of the Internet Name Space", 15 December 2023.

Security and Stability Advisory Committee. Advises the ICANN community and Board on matters relating to the security and integrity of the Internet's naming and address allocation systems (ICANN Bylaws).

At-Large Advisory Committee. Considers and provides advice on the activities of ICANN related to the interests of individual Internet users (ICANN Bylaws). Not to be confused with the Non-Commercial Stakeholder Group.

Request For Comments. Archival series dedicated to documenting Internet technical specifications, including general contributions from the Internet research and engineering community as well as standards documents (RFC Editor Model, Version 3).

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