.gb

Infobox Top level domain
name=.gb
background=#CCF
introduced=1985
type=Country code top-level domain
status=retired
registry=JANET(UK)
sponsor=JANET(UK)
intendeduse=Entities connected with United Kingdom
actualuse=Fallen into disuse in favour of .uk
restrictions=No registrations presently being taken
structure=Government sites formerly found under hmg.gb
document=
disputepolicy=None
website=None|

.gb is a reserved Internet country code top-level domain (ccTLD) for the United Kingdom. Introduced at the same time as the UK's other top-level domain (.uk), it was never widely used. It is no longer possible to register under this domain.

The rule in the Domain Name System is that a top-level domain for a country is derived from the corresponding two-letter code in the ISO 3166-1 list. Accordingly the correct code for the United Kingdom of Great Britain and Northern Ireland is GB, and the .gb top-level domain was therefore delegated.

The pre-existing JANET Name Registration Scheme had used "UK" as a country code, so the UK also applied to Jon Postel of IANA for the .uk TLD. This was granted, and all UK domain names are now issued as .uk, rather than .gb.

.gb was used for a number of years, mainly by UK 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. [cite web|url=http://www.nsrc.org/codes/bymap/notes.html|title=International E-mail Accessibility|last=Crepin-Leblond|first=Olivier M.J.|date=2003|accessdate=2008-06-23]

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.

One .gb subdomain still exists in the DNS (as of 2008): dra.hmg.gb, belonging to Her Majesty's Government's former Defence Research Agency.

References

External links

* [http://www.iana.org/root-whois/gb.htm IANA .gb whois information]
* [http://www.ja.net/ JANET(UK) website]
* [http://web.archive.org/web/20021016114822/http://www.dra.hmg.gb/newsite/home_2.htm www.dra.hmg.gb] Last accessible copy of www.dra.hmg.gb in the Internet Archive