HOME

TheInfoList



OR:

Reverse domain name notation (or reverse-DNS) is a naming convention for components, packages, types or file names used by a programming language, system or framework. Reverse-DNS strings are based on registered domain names, with the order of the components reversed for grouping purposes. For example, if a company making the product "MyProduct" has the
domain name A domain name is a string that identifies a realm of administrative autonomy, authority or control within the Internet. Domain names are often used to identify services provided through the Internet, such as websites, email services and more. As ...
example.com, they could use the reverse-DNS string com.example.MyProduct as an identifier for that product. Reverse-DNS names are a simple way of eliminating namespace collisions, since any domain name is globally unique to its registered owner.


History

The first appearance of reversed DNS strings predated the Internet domain name standards. The UK Joint Academic Networking Team (
JANET Janet may refer to: Names * Janet (given name) * Janet (French singer) (1939–2011) Surname * Charles Janet (1849–1932), French engineer, inventor and biologist, known for the Left Step periodic table * Jules Janet (1861–1945), French psych ...
) used this order in its Name Registration Scheme, before the Internet domain name standard was established. For example, the name uk.ac.bris.pys.as was interpreted as a host named as within the UK (top level domain
.uk .uk is the Internet country code top-level domain (ccTLD) for the United Kingdom. It was first registered in July 1985, seven months after the original generic top-level domains such as .com and the first country code after .us. , it is the fift ...
), while the Internet standard would have interpreted it as a host named uk within the American Samoa top level domain (
.as .as is the Internet country code top-level domain (ccTLD) for American Samoa. It is administered by AS Domain Registry. Island Networks, which provides registry services for .gg and .je, is also responsible for the technical operations of . ...
). During the period while both JANET-style and Internet-style addresses were in use, mailers and gateway sites had ad-hoc workarounds to handle the differences, but could still be confused. Reverse-DNS for identifier strings first became widely used with the
Java platform Java is a set of computer software and specifications developed by James Gosling at Sun Microsystems, which was later acquired by the Oracle Corporation, that provides a system for developing application software and deploying it in a cro ...
.


Examples

Examples of systems that use reverse-DNS notation are: *
Sun Microsystems Sun Microsystems, Inc. (Sun for short) was an American technology company that sold computers, computer components, software, and information technology services and created the Java programming language, the Solaris operating system, ZFS, t ...
'
Java platform Java is a set of computer software and specifications developed by James Gosling at Sun Microsystems, which was later acquired by the Oracle Corporation, that provides a system for developing application software and deploying it in a cro ...
for namespaces *
Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus '' Malus''. The tree originated in Central Asia, where its wild ancest ...
's Uniform Type Identifier (UTI) * The Android operating system, for classifying applications (because the Dalvik virtual machine was based on Java) *
dconf dconf is a low-level configuration system and settings management tool. Its main purpose is to provide a back end to GSettings on platforms that don't already have configuration storage systems. It depends on GLib. It is part of GNOME 3 and ...
, the configuration backend used by
GNOME A gnome is a mythological creature and diminutive spirit in Renaissance magic and alchemy, first introduced by Paracelsus in the 16th century and later adopted by more recent authors including those of modern fantasy literature. Its characte ...
* The freedesktop.org Desktop Entry Specification Some examples of reverse-DNS strings are: * com.adobe.postscript-font, UTI string for
Adobe Systems Adobe Inc. ( ), originally called Adobe Systems Incorporated, is an American multinational computer software company incorporated in Delaware and headquartered in San Jose, California. It has historically specialized in software for the cre ...
's
PostScript PostScript (PS) is a page description language in the electronic publishing and desktop publishing realm. It is a dynamically typed, concatenative programming language. It was created at Adobe Systems by John Warnock, Charles Geschke, Do ...
fonts * com.apple.ostype, UTI string for
Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus '' Malus''. The tree originated in Central Asia, where its wild ancest ...
's
OSType A FourCC ("four-character code") is a sequence of four bytes (typically ASCII) used to uniquely identify data formats. It originated from the OSType or ResType metadata system used in classic Mac OS and was adopted for the Amiga/Electronic Arts I ...
* org.omg.CORBA,
Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...
library for
CORBA The Common Object Request Broker Architecture (CORBA) is a standard defined by the Object Management Group (OMG) designed to facilitate the communication of systems that are deployed on diverse platforms. CORBA enables collaboration between s ...
* org.w3c.dom,
Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...
library for W3C's DOM * org.kde.dolphin.desktop, a
desktop A desktop traditionally refers to: * The surface of a desk (often to distinguish office appliances that fit on a desk, such as photocopiers and printers, from larger equipment covering its own area on the floor) Desktop may refer to various compu ...
file name


See also

*
Non-Internet email address A wide variety of non-Internet email address formats were used in early email systems before the ubiquity of the ''[email protected]'' form used by Internet mail systems since the 1980s - and a few are still used in specialised contexts. Sin ...


References

{{Reflist


External links


Eclipse Naming Conventions


Domain Name System