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Introduced 1985
TLD type Country code top-level domain
Status Unused
Registry JANET(UK)
Sponsor JANET(UK)
Intended use Entities connected with  United Kingdom
Actual use Fallen into disuse in favour of .uk
Registration restrictions No registrations presently being taken
Structure Government sites formerly found under hmg.gb
Dispute policies None
Website None

.gb is a reserved Internet country code top-level domain (ccTLD) for the United Kingdom.

The domain was introduced with RFC 920[1] in October 1984 that set out the creation of ccTLD generally using country codes derived from the corresponding two-letter code in the ISO 3166-1 list. However, the .uk domain had been created separately a few months before the compilation of this list.[2] Consequently, .gb was never widely used. It is no longer possible to register under this domain.

.gb was used for a number of years, mainly by British government organisations and commercial e-mail services using X.400-based e-mail infrastructure. This simplified translating between DNS domains and X.400 addresses, which used "GB" as a country code.[3]

With the demise of X.400 e-mail and IANA's general aim of one TLD per country, use of .gb declined; the domain remains in existence, but it is not open to new subdomain registrations.


  1. J. Postel and J. Reynolds (October 1984), Request for Comments: 920, Network Working Group<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  2. Milton Mueller (2002), Ruling the Root: Internet Governance and the Taming of Cyberspace, Cambridge, Massachusetts: MIT Press, p. 79, ISBN 9780262632980<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  3. Crepin-Leblond, Olivier M. J. (2003). "International E-mail Accessibility". Archived from the original on 21 May 2008. Retrieved 23 June 2008.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>

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