Special-use domain name
A special-use domain name is a domain name that is defined and reserved in the hierarchy of the Domain Name System of the Internet for special purposes. The designation of a reserved special-use domain is authorized by the Internet Engineering Task Force (IETF) and executed, maintained, and published by the Internet Assigned Numbers Authority (IANA).[1]
Reserved domain names
The following list comprises the domain names list by IANA in the category of special-use domain names.[2]
| Domain | Purpose | Authority document |
|---|---|---|
| .alt | Preventing name collisions with DNS | RFC 9476[3] |
| 6tisch.arpa | IETF 6TiSCH working group | RFC 9031[4] |
| 10.in-addr.arpa | Reverse zones for IPv4 private networks (see AS112) | RFC 6761[1] |
| 16.172.in-addr.arpa | ||
| 17.172.in-addr.arpa | ||
| 18.172.in-addr.arpa | ||
| 19.172.in-addr.arpa | ||
| 20.172.in-addr.arpa | ||
| 21.172.in-addr.arpa | ||
| 22.172.in-addr.arpa | ||
| 23.172.in-addr.arpa | ||
| 24.172.in-addr.arpa | ||
| 25.172.in-addr.arpa | ||
| 26.172.in-addr.arpa | ||
| 27.172.in-addr.arpa | ||
| 28.172.in-addr.arpa | ||
| 29.172.in-addr.arpa | ||
| 30.172.in-addr.arpa | ||
| 31.172.in-addr.arpa | ||
| 168.192.in-addr.arpa | ||
| 170.0.0.192.in-addr.arpa | NAT64 prefix discovery[5] | RFC 8880[6] |
| 171.0.0.192.in-addr.arpa | ||
| ipv4only.arpa | ||
| 254.169.in-addr.arpa | Reverse zone for the IPv4 link-local address space[7] | RFC 6762[8] |
| 8.e.f.ip6.arpa | Reverse zones for the IPv6 link-local address space[9] | |
| 9.e.f.ip6.arpa | ||
| a.e.f.ip6.arpa | ||
| b.e.f.ip6.arpa | ||
| .eap.arpa | Extensible Authentication Protocol | RFC 9965[10] |
| .eap-noob.arpa | ||
| .home.arpa | Non-unique use in residential networks | RFC 8375[11] |
| .resolver.arpa | Facilitate upgrading to encrypted DNS | RFC 9462[12] |
| .service.arpa | DNS-based service discovery | RFC 9665[13] |
| .example | Documentation, tutorials, or testing[14] | RFC 6761[1] |
| example.com | ||
| example.net | ||
| example.org | ||
| .invalid | ||
| .test | ||
| .local | Used in multicast DNS (mDNS) | RFC 6762[8]: §3 |
| .localhost | Refers to the loopback addresses (:: and 127.0.0.1) | RFC 6761[1] |
| .onion | Tor network onion services | RFC 7686[15] |
See also
- .internal, reserved by ICANN
- Reserved top-level domains
References
- 1 2 3 4 S. Cheshire; M. Krochmal (February 2013). Special-Use Domain Names. Internet Engineering Task Force. doi:10.17487/RFC6761. ISSN 2070-1721. RFC 6761. Proposed Standard. Updates RFC 1918 and 2606.
- ↑ "Special-Use Domain Names". Internet Assigned Number Authority. Retrieved 2026-07-12.
- ↑ W. Kumari; MP. Hoffman (September 2023). The .alt Special-Use Top-Level Domain. Internet Engineering Task Force. doi:10.17487/RFC9476. ISSN 2070-1721. RFC 9476. Proposed Standard.
- ↑ J. Simon; K. Pister; M. Richardson (May 2021). M. Vučinić (ed.). Constrained Join Protocol (CoJP) for 6TiSCH. Internet Engineering Task Force. doi:10.17487/RFC9031. ISSN 2070-1721. RFC 9031. Proposed Standard.
- ↑ T. Savolainen; J. Korhonen; D. Wing (November 2013). Discovery of the IPv6 Prefix Used for IPv6 Address Synthesis. Internet Engineering Task Force. doi:10.17487/RFC7050. ISSN 2070-1721. RFC 7050. Proposed Standard. Updated by RFC 8880.
- ↑ S. Cheshire; D. Schinazi (August 2020). Special Use Domain Name 'ipv4only.arpa'. Internet Engineering Task Force. doi:10.17487/RFC8880. ISSN 2070-1721. RFC 8880. Proposed Standard. Updates RFC 7788.
- ↑ S. Cheshire; B. Aboba; E. Guttman (May 2005). Dynamic Configuration of IPv4 Link-Local Addresses. Network Working Group. doi:10.17487/RFC3927. RFC 3927. Proposed Standard.
- 1 2 S. Cheshire; M. Krochmal (February 2013). Multicast DNS. Internet Engineering Task Force. doi:10.17487/RFC6762. ISSN 2070-1721. RFC 6762. Proposed Standard.
- ↑ R. Hinden; S. Deering (February 2006). IP Version 6 Addressing Architecture. Network Working Group. doi:10.17487/RFC4291. RFC 4291. Draft Standard. Obsoletes RFC 3513. Updated by RFC 5952, 6052, 7136, 7346, 7371 and 8064.
- ↑ A. DeKok (May 2026). The eap.arpa. Domain and Extensible Authentication Protocol (EAP) Provisioning. Internet Engineering Task Force (IETF). doi:10.17487/RFC9965. RFC 9965. Proposed Standard. Updates RFC 5216, 9140 and 9190.
- ↑ P. Pfister; T. Lemon (May 2018). Special-Use Domain 'home.arpa.'. Internet Engineering Task Force. doi:10.17487/RFC8375. ISSN 2070-1721. RFC 8375. Proposed Standard. Updates RFC 7788.
- ↑ T. Pauly; E. Kinnear; C. A. Wood; P. McManus; T. Jensen (November 2023). Discovery of Designated Resolvers. Internet Engineering Task Force. doi:10.17487/RFC9462. ISSN 2070-1721. RFC 9462. Proposed Standard.
- ↑ T. Lemon; S. Cheshire (June 2025). Service Registration Protocol for DNS-Based Service Discovery. Internet Engineering Task Force. doi:10.17487/RFC9665. RFC 9665. Proposed Standard.
- ↑ D. Eastlake; A. Panitz (June 1999). Reserved Top Level DNS Names. Network Working Group. doi:10.17487/RFC2606. BCP 32. RFC 2606. Best Current Practice 32. Updated by RFC 6761.
- ↑ J. Appelbaum; A. Muffett (October 2015). The ".onion" Special-Use Domain Name. Internet Engineering Task Force. doi:10.17487/RFC7686. ISSN 2070-1721. RFC 7686. Proposed Standard.