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Network Information Centre

Network Information Centre

A Network Information Centre (NIC), also known as domain registry, is part of the Domain Name System of the Internet. In addition to the world roots, each top level domain will have its own NIC. For example www.nic.uk is Nominet UK, the country code registry for the United Kingdom top level domain, and www.nic.es is the Spanish country code registry.

Domain Name System

The Domain Name System (DNS) is a system that stores information associated with domain names in a distributed database on networks, such as the Internet. The domain name system associates many types of information with domain names, but most importantly, it provides the IP address associated with the domain name. It also lists mail exchange servers accepting e-mail for each domain. This means that DNS is involved with each page visit on the internet and with each email message sent. DNS is useful for several reasons. Most well known, the DNS makes it possible to attach hard-to-remember IP addresses (such as 207.142.131.206) to easy-to-remember domain names (such as "wikipedia.org") Humans take advantage of this when they recite URLs and e-mail addresses. Less recognized, the domain name system makes it possible for people to assign authoritative names, without needing to communicate with a central registrar each time.

A brief history of the DNS

The practice of using a name as a more human-legible abstraction of a machine's numerical address on the network predates even TCP/IP, all the way back to the ARPAnet era. Originally, each computer on the network retrieved a file called HOSTS.TXT from SRI (now SRI International) which mapped an address (eg. 192.0.2.135) to a name (eg. www.example.com.) The Hosts file still exists on most modern operating systems either by default or through configuration and allows users to specify an IP Address to use for a hostname without checking the DNS. This file is now used primarily for troubleshooting DNS errors or mapping local addresses to more organic names. Such a system had inherent limitations, because of the obvious requirement that every time a given computer's address changed, every computer that wanted to communicate with it would need an update to its Hosts file. The growth of networking called for a more scalable system: one which recorded a change in a host's address in one place only. Other hosts would learn about the change dynamically through a notification system, thus completing a globally accessible network of all hosts' names and their associated IP Addresses. Enter the DNS. Paul Mockapetris invented the DNS in 1983; the original specifications appear in RFC 882 and 883. In 1987, the publication of RFC 1034 and RFC 1035 updated the DNS specification and made RFC 882 and RFC 883 obsolete. Several more recent RFCs have proposed various extensions to the core DNS protocols.

How the DNS works in theory

Actors

1987 The domain name space is a gigantic tree of domain names. Each node or leaf in the tree is associated with resource records, which hold the information associated with the domain name. The tree is divided into zones. A zone is a collection of connected nodes that are authoritatively served by an authoritative DNS nameserver. (Note that a single nameserver can host several zones.) When a system administrator wants to let another administrator control a part of the domain name space within his or her zone of authority, he or she can delegate control to the other administrator. This splits a part of the old zone off into a new zone, which is served by the second administrator's nameservers. The old zone is no longer authoritative for what is under the authority of the new zone. The information associated with nodes is looked up by a resolver. A resolver knows how to communicate with name servers by sending DNS requests, and heeding DNS responses. Resolving usually entails recursing through several name servers to find the needed information. Some resolvers are simple, and can only communicate with a single name server. These simple resolvers rely on a recursing name server to perform the work of finding information for it.

Understanding the parts of a domain name

A domain name usually consists of two or more parts (technically labels), separated by dots. For example wikipedia.org.
- The rightmost label conveys the top-level domain (for example, the address en.wikipedia.org has the top-level domain org).
- Each label to the left specifies a subdivision or subdomain of the domain above it. Note that "subdomain" expresses relative dependence, not absolute dependence: for example, wikipedia.org comprises a subdomain of the org domain, and en.wikipedia.org could form a subdomain of the domain wikipedia.org (in practice, however, en.wikipedia.org actually represents a hostname). In theory, this subdivision can go down to 127 levels deep, and each label can contain up to 63 characters, as long as the whole domain name does not exceed a total length of 255 characters. But in practice some domain registries have shorter limits than that.
- Finally, the leftmost part of the domain name (usually) expresses the hostname. The rest of the domain name simply specifies a way of building a logical path to the information required; the hostname is the actual target system name for which an IP address is desired. For example, the domain name en.wikipedia.org has the hostname "en". The DNS consists of a hierarchical set of DNS servers. Each domain or subdomain has one or more authoritative DNS servers that publish information about that domain and the name servers of any domains "beneath" it. The hierarchy of authoritative DNS servers matches the hierarchy of domains. At the top of the hierarchy stand the root servers: the servers to query when looking up (resolving) a top-level domain name.

An example of theoretical DNS recursion

root servers An example may clarify this process. Suppose an application needs to find the IP address of www.wikipedia.org. It puts this question to a local DNS recursor.
- Before starting, the recursor has to know where to find the root servers; administrators of recursive DNS servers manually specify (and periodically update) a file called the root hints which specify recently known IP addresses of these servers, from which the DNS server can obtain a current complete list.
- The process starts by the recursor asking one of these root servers - for example, the server with the IP address "198.41.0.4" - the question "what is the IP address for www.wikipedia.org?"
- The root server replies with a delegation, meaning roughly: "I don't know the IP address of www.wikipedia.org, but I do know that the DNS server at 204.74.112.1 has information on the org domain."
- The local DNS recursor then asks that DNS server (i.e. 204.74.112.1) the same question it had previously put to the root servers, i.e. "what is the IP address for www.wikipedia.org?". It gets a similar reply - essentially, "I don't know the address of www.wikipedia.org, but I do know that the DNS server at 207.142.131.234 has information on the wikipedia.org domain."
- Finally the request goes to this third DNS server (207.142.131.234), which replies with the required IP address. This process utilises recursive searching.

Understanding domain registration and glue records

Reading the example above, you might reasonably wonder: "how does the DNS server 204.74.112.1 know what IP address to give out for the wikipedia.org domain?" In the first step of the process, we noted that a DNS recursor has the IP addresses of the root servers more-or-less hard coded. Equally, the name servers that are authoritative for the Top-Level Domains change very infrequently. However, the name servers that provide authoritative answers for common domain names may change relatively often. As part of the process of registering a domain name (and at any time thereafter), a registrant provides the registry with the name servers that will be authoritative for that domain name; therefore, when registering wikipedia.org, that domain is associated with the name servers gunther.bomis.com and zwinger.wikipedia.org at the .org registry. Consequently, in the example above, when the server identified by 204.74.112.1 receives a request, the DNS server scans its list of domains, locates wikipedia.org, and returns the name servers associated with that domain. Name servers in delegations are listed by name, rather than by IP address. This means that a resolving name server must issue another DNS request to find out the IP address of the server to which it has been referred. Since this can introduce a bootstrapping problem when the name of the nameserver is in the domain about which nothing is yet known, it is occasionally necessary for the nameserver providing the delegation to also provide the IP address of the next nameserver. This record is called a glue record.

DNS in practice

When an application (such as a web browser) tries to find the IP address of a domain name, it doesn't necessarily follow all of the steps outlined in the Theory section above. We will first look at the concept of caching, then outline the operation of DNS in "the real world".

Caching and time to live

Because of the huge volume of requests generated by a system like the DNS, the designers wished to provide a mechanism to reduce the load on individual DNS servers. The mechanism devised provided that when a DNS resolver (i.e. client) received a DNS response, it would cache that response for a given period of time. A value (set by the administrator of the DNS server handing out the response) called the time to live, or TTL defines that period of time. Once a response goes into cache, the resolver will consult its cached (stored) answer; only when the TTL expires (or until an administrator manually flushes the response from the resolver's memory) will the resolver contact the DNS server for the same information. Generally, the time to live is specified in the Start of Authority (SOA) record. SOA parameters are:
- Serial — the zone serial number, incremented when the zone file is modified, so the slave and secondary name servers know when the zone has been changed and should be reloaded.
- Refresh — This is the number of seconds between update requests from secondary and slave name servers.
- Retry — This is the number of seconds the secondary or slave will wait before retrying when the last attempt has failed.
- Expire — This is the number of seconds before a master or slave will wait before considering the data stale if it cannot reach the primary name server.
- Minimum — Previously used to determine the minimum TTL, this is used for negative caching. (Newer versions of named will accept 'M','H','D' & 'W' suffixes indicating that the time interval is respectively in Minutes, Hours, Days and Weeks).

Caching time

An important consequence of this distributed and caching architecture is that changes to the DNS are not always immediately effective globally. This is best explained with an example: If an administrator has set a TTL of 6 hours for the host www.wikipedia.org, and then changes the IP address to which www.wikipedia.org resolves at 12:01pm, the administrator must consider that a person who cached a response with the old IP Address at 12:00pm will not consult the DNS server again until 6:00pm. The period between 12:01pm and 6:00pm in this example is called caching time, which is best defined as a period of time that begins when you make a change to a DNS record and ends after the maximum amount of time specified by the TTL expires. This essentially leads to an important logistical consideration when making changes to the DNS: not everyone is necessarily seeing the same thing you're seeing. [http://www.ietf.org/rfc/rfc1537.txt RFC1537] helps to convey basic rules for how to set the TTL. Note that the term "propagation", although very widely used, is a poor term to describe the effects of caching. Specifically, it implies that [1] when you make a DNS change, it somehow spreads to all other DNS servers (instead, other DNS servers check in with yours as needed), and [2] that you do not have control over the amount of time the record is cached (you have complete control for all DNS records on your domain, except your NS records and any authoritative DNS servers that use your domain name). Many people incorrectly refer to a mysterious 48 hour or 72 hour propagation time when you make a DNS change. When you change the NS records for your domain or the IP addresses for hostnames of authoritative DNS servers using your domain (if any), there can be a lengthy period of time before all DNS servers use the new information. This is because those records are handled by the zone parent DNS servers (for example, the .com DNS servers if your domain is example.com), which typically cache those records for 48 hours. However, those DNS changes will be immediately available for any DNS servers that do not have them cached. And, any DNS changes on your domain other than the NS records and authoritative DNS server names can be nearly instantaneous, if you choose for them to be (by lowering the TTL once or twice ahead of time, and waiting until the old TTL expires before making the change).

DNS in the real world

TTL Users generally do not communicate directly with a DNS resolver. Instead DNS resolution is handled transparently via client applications such as web browsers (Mozilla Firefox, Safari, Opera, Internet Explorer, etc), mail clients (Outlook Express, Mozilla Thunderbird, etc), and other internet applications. When a request is made which necessitates a DNS lookup, such programs send a resolution request to the local DNS resolver in the operating system which in turn handles the communications required. The DNS resolver will almost invariably have a cache (see above) containing recent lookups. If the cache can provide the answer to the request, the resolver will return the value in the cache to the program that made the request. If the cache does not contain the answer, the resolver will send the request to a designated DNS server or servers. In the case of most home users, the Internet service provider to which the machine connects will usually supply this DNS server: such a user will either configure that server's address manually or allow DHCP to set it; however, where systems administrators have configured systems to use their own DNS servers, their DNS resolvers will generally point to their own nameservers. This name server will then follow the process outlined above in DNS in theory, until it either successfully finds a result, or does not. It then returns its results to the DNS resolver; assuming it has found a result, the resolver duly caches that result for future use, and hands the result back to the software which initiated the request. As a final level of complexity, some applications such as Web browsers also have their own DNS cache, in order to reduce use of the DNS resolver library itself, which can add extra difficulty to DNS debugging, as it obscures which data is fresh, or lies in which cache. These caches typically have very short caching times of the order of 1 minute. A notable exception is Internet Explorer. Recent versions cache DNS records for 30 minutes[http://support.microsoft.com/default.aspx?scid=KB;en-us;263558].

Other DNS applications

The system outlined above provides a somewhat simplified scenario. The DNS includes several other functions:
- Hostnames and IP addresses do not necessarily match on a one-to-one basis. Many hostnames may correspond to a single IP address: combined with virtual hosting, this allows a single machine to serve many web sites. Alternatively a single hostname may correspond to many IP addresses: this can facilitate fault tolerance and load distribution, and also allows a site to move physical location seamlessly.
- There are many uses of DNS besides translating names to IP addresses. For instance, Mail transfer agents use DNS to find out where to deliver e-mail for a particular address. The domain to mail exchanger mapping provided by MX records accommodates another layer of fault tolerance and load distribution on top of the name to IP address mapping.
- Sender Policy Framework controversially takes advantage of a DNS record type, the TXT record.
- To provide resilience in the event of computer failure, multiple DNS servers provide coverage of each domain. In particular, thirteen root servers exist worldwide. DNS programs or operating systems have the IP addresses of these servers built in. The USA hosts, at least nominally, all but three of the root servers. However, because many root servers actually implement anycast, where many different computers can share the same IP address to deliver a single service over a large geographic region, most of the physical (rather than nominal) root servers now operate outside the USA. The DNS uses TCP and UDP on port 53 to serve requests. Almost all DNS queries consist of a single UDP request from the client followed by a single UDP reply from the server. TCP typically comes into play only when the response data size exceeds 512 bytes, or for such tasks as zone transfer.

Standards

- RFC 1034 Domain Names - Concepts and Facilities.
- RFC 1035 Domain Names - Implementation and Specification.
- RFC 1183 New DNS RR Definitions
- RFC 1706 DNS NSAP Resource Records
- RFC 1876 Location Information in the DNS (LOC)
- RFC 1886 DNS Extensions to support IP version 6
- RFC 1912 Common DNS Operational and Configuration Errors
- RFC 1995 Incremental Zone Transfer in DNS
- RFC 1996 A Mechanism for Prompt Notification of Zone Changes (DNS NOTIFY)
- RFC 2136 Dynamic Updates in the Domain Name System (DNS UPDATE)
- RFC 2181 Clarifications to the DNS Specification
- RFC 2308 Negative Caching of DNS Queries (DNS NCACHE)
- RFC 2317 Classless IN-ADDR.ARPA delegation
- RFC 2672 Non-Terminal DNS Name Redirection
- RFC 2782 A DNS RR for specifying the location of services (DNS SRV)
- RFC 2845 Secret Key Transaction Authentication for DNS (TSIG)
- RFC 2874 DNS Extensions to Support IPv6 Address Aggregation and Renumbering
- RFC 3403 Dynamic Delegation Discovery System (DDDS) (NAPTR records)

Types of DNS records

Important categories of data stored in the DNS include the following:
- An A record or address record maps a hostname to a 32-bit IPv4 address.
- An AAAA record or IPv6 address record maps a hostname to a 128-bit IPv6 address.
- A CNAME record or canonical name record makes one domain name an alias of another. The aliased domain gets all the subdomains and DNS records of the original.
- An MX record or mail exchange record maps a domain name to a list of mail exchange servers for that domain.
- A PTR record or pointer record maps an IPv4 address to the canonical name for that host. Setting up a PTR record for a hostname in the in-addr.arpa domain that corresponds to an IP address implements reverse DNS lookup for that address. For example (at the time of writing), www.icann.net has the IP address 192.0.34.164, but a PTR record maps 164.34.0.192.in-addr.arpa to its canonical name, referrals.icann.org.
- An NS record or name server record maps a domain name to a list of DNS servers authoritative for that domain. Delegations depend on NS records.
- An SOA record or start of authority record specifies the DNS server providing authoritative information about an Internet domain, the email of the domain administrator, the domain serial number, and several timers relating to refreshing the zone.
- An SRV record is a generalized service location record.
- A TXT record allows an administrator to insert arbitrary text into a DNS record. For example, this record is used to implement the Sender Policy Framework specification. Other types of records simply provide information (for example, a LOC record gives the physical location of a host), or experimental data (for example, a WKS record gives a list of servers offering some well-known service such as HTTP or POP3 for a domain).

Internationalised domain names

Domain names must use only a subset of ASCII characters—the Roman alphabet in upper and lower case, the digits 0 through 9, and the hyphen. This prevented the representation of names and words of many languages natively. ICANN has approved the Punycode-based IDNA system, which maps Unicode strings into the valid DNS character set, as a workaround to this issue. Some registries have adopted IDNA.

DNS software

Various flavors of DNS software implement the DNS, including:
- BIND (Berkeley Internet Name Daemon) – full featured, most popular, de facto Internet standard
- djbdns (Daniel J. Bernstein's DNS) – composed of several small-footprint components
- MaraDNS – UDP only
- VitalQIP (Lucent Technologies)
- Adonis DNS Management Appliance (BlueCat Networks Inc)
- NSD (Name Server Daemon) – small footprint, UDP only, authoritative only
- PowerDNS
- Microsoft DNS (in the server editions of Windows 2000 and Windows 2003)
- Simple DNS Plus (JH Software) - shareware, runs on Windows DNS-oriented utilities include:
- dig (the "domain information groper")
- mysqlBind - BIND 8/9 DNS server administration system for one or hundreds of DNS servers. GPL licensed.

Legal users of domains

Registrant

No one in the world really "owns" a domain name except the Network Information Centre (NIC), or domain name registry. Most of the NICs in the world receive an annual fee from a legal user in order for the legal user to utilise the domain name (i.e. a sort of a leasing agreement exists, subject to the registry's terms and conditions). Depending on the various naming convention of the registries, legal users become commonly known as "registrants" or as "domain holders". ICANN holds a complete list of domain registries in the world. One can find the legal user of a domain name by looking in the WHOIS database held by most domain registries. For most of the more than 240 country code top-level domains (ccTLDs), the domain registries hold the authoritative WHOIS (Registrant, name servers, expiry dates etc). For instance, DENIC, Germany NIC holds the authoritative WHOIS to a .DE domain name. However, some domain registries, such as VeriSign, use a registry-registrar model. There are hundreds of Domain Name Registrars that actually perform the domain name registration with the end-user, such as eNom. By using this method of distribution, the registry only has to manage the relationship with the registrar, and the registrar maintains the relationship with the end-users, or 'registrants'. For .COM, .NET domain names, the domain registries, VeriSign holds a basic WHOIS (registrar and name servers etc). One can find the detailed WHOIS (Registrant, name servers, expiry dates etc) at the registrars. Since about 2001, most gTLD registries (.ORG, .BIZ, .INFO) have adopted a so-called "thick" registry approach, i.e. keeping the authoritative WHOIS with the various registries instead of the registrars.

Administrative contact

A registrant usually designates an administrative contact to manage the domain name. In practice, the administrative contact usually has the most immediate power over a domain. Management functions delegated to the administrative contacts may include (for example):
- the obligation to conform to the requirements of the domain registry in order to retain the right to use a domain name
- authorisation to update the physical address, e-mail address and telephone number etc in WHOIS

Technical contact

A technical contact manages the name servers of a domain name. The many functions of a technical contact include:
- making sure the configurations of the domain name conforms to the requirements of the domain registry
- updating the domain zone
- providing the 24x7 functionality of the name servers (that leads to the accessibility of the domain name)

Billing contact

Self-explanatory, the party whom a NIC invoices.

Name servers

Namely the authoritative name servers that host the domain name zone of a domain name.

Politics

Many investigators have voiced criticism of the methods used currently to control ownership of domains. Most commonly, critics claim abuse by monopolies or near-monopolies, such as VeriSign, Inc., and problems with assignment of top-level domains. The international body ICANN (the Internet Corporation for Assigned Names and Numbers) oversees the domain name industry.

Truth in Domain Names Act

In the United States, the "Truth in Domain Names Act", in combination with the PROTECT Act, forbids the use of a misleading domain name with the intention of attracting people into viewing a visual depiction of sexually explicit conduct on the internet

External links and documentation

- [http://www.linux.ie/articles/dns.php All About DNS]
- [http://www.linux.ie/articles/tutorials/dns-tsig.php Securing DNS with Transaction Signatures]
- [http://www.nap.edu/execsumm_pdf/11258.pdf Signposts in Cyberspace: The Domain Name System and Internet Navigation (PDF format)]
- [http://cr.yp.to/djbdns/forgery.html DNS Forgery]
- [http://ketil.froyn.name/poison.html DNS Poisoning, a practical example]
- [http://www.windowsnetworking.com/articles_tutorials/Quickly-Test-DNS-Resolution.html How to 'Quickly' Test DNS Resolution]
- [http://www.ckdhr.com/dns-loc/sites.html Sites supporting DNS LOC]
- [http://www.bind9.net/dns-links Domain Name System Links, Whitepapers, and Research]
- [http://www.dnswatch.info DNS lookups] shows recursive search process during dns lookup
- [http://www.adminschoice.com/docs/domain_name_service.htm Setting up DNS server in unix]
- [http://www.DNSstuff.com Online DNS tools]
- [http://support.microsoft.com/default.aspx?scid=KB;en-us;263558 Microsoft KB Article on IE Cache Times]
- [http://pdos.csail.mit.edu/chord/papers/ddns.pdf Serving DNS using a Peer-to-Peer Lookup Service]
- [http://distributeddns.sourceforge.net/ Distributed DNS] Category:Internet standards Category:Internet protocols ko:DNS ms:Sistem Nama Domain ja:Domain Name System

Internet

:For the more general networking concept, see internetworking. The Internet, or simply the Net, is the worldwide system of interconnected computer networks which makes information stored on it accessible. This information is transmitted by packet switching using a standardized Internet Protocol (IP) and many other protocols. It is made up of thousands of smaller commercial, academic, domestic and government networks. It carries various information and services, such as electronic mail, online chat, and the interlinked web pages and other documents of the World Wide Web.

Creation of the Internet

During the 1950s, several communications researchers realized that there was a need to allow general communication between users of various computers and communications networks. This led to research into decentralized networks, queuing theory, and packet switching. The subsequent creation of ARPANET in the United States in turn catalyzed a wave of technical developments that made it the basis for the development of the Internet. Contrary to popular myth, the DoD did not create the ARPANET so that they could communicate to the US Government after a nuclear war. The first TCP/IP wide area network was operational in 1984 when the United States' National Science Foundation (NSF) constructed a university network backbone that would later become the NSFNet. It was then followed by the opening of the network to commercial interests in 1995. Important separate networks that offered gateways into, then later merged into the Internet include Usenet, Bitnet and the various commercial and educational X.25 networks such as Compuserve and JANET. The ability of TCP/IP to work over these pre-existing communication networks allowed for a great ease of growth. Use of Internet as a phrase to describe a single global TCP/IP network originated around this time. The collective network gained a public face in the 1990s. In August 1991 CERN in Switzerland publicized the new World Wide Web project, two years after Tim Berners-Lee had begun creating HTML, HTTP and the first few web pages at CERN in Switzerland. In 1993 the Mosaic web browser version 1.0 was released, and by late 1994 there was growing public interest in the previously academic/technical Internet. By 1996 the word "Internet" was common public currency, but it referred almost entirely to the World Wide Web. Meanwhile, over the course of the decade, the Internet successfully accommodated the majority of previously existing public computer networks (although some networks such as FidoNet have remained separate). This growth is often attributed to the lack of central administration, which allows organic growth of the network, as well as the non-proprietary open nature of the Internet protocols, which encourages vendor interoperability and prevents any one company from exerting too much control over the network.

Today's Internet

FidoNets, FTP client, and Telnet client]] Apart from the complex physical connections that make up its infrastructure, the Internet is held together by bi- or multi-lateral commercial contracts (for example peering agreements) and by technical specifications or protocols that describe how to exchange data over the network. Indeed, the Internet is essentially defined by its interconnections and routing policies. In an often-cited, if perhaps gratuitously mathematical definition, Seth Breidbart once described the Internet as "the largest equivalence class in the reflexive, transitive, symmetric closure of the relationship 'can be reached by an IP packet from'". Unlike older communications systems, the Internet protocol suite was deliberately designed to be independent of the underlying physical medium. Any communications network, wired or wireless, that can carry two-way digital data can carry Internet traffic. Thus, Internet packets flow through wired networks like copper wire, coaxial cable, and fiber optic; and through wireless networks like Wi-Fi. Together, all these networks, sharing the same high-level protocols, form the Internet. The Internet protocols originate from discussions within the Internet Engineering Task Force (IETF) and its working groups, which are open to public participation and review. These committees produce documents that are known as Request for Comments documents (RFCs). Some RFCs are raised to the status of Internet Standard by the Internet Architecture Board (IAB). Some of the most used protocols in the Internet protocol suite are IP, TCP, UDP, DNS, PPP, SLIP, ICMP, POP3, IMAP, SMTP, HTTP, HTTPS, SSH, Telnet, FTP, LDAP, SSL, and TLS. Some of the popular services on the Internet that make use of these protocols are e-mail, Usenet newsgroups, file sharing, Instant Messenger, the World Wide Web, Gopher, session access, WAIS, finger, IRC, MUDs, and MUSHs. Of these, e-mail and the World Wide Web are clearly the most used, and many other services are built upon them, such as mailing lists and blogs. The Internet makes it possible to provide real-time services such as Internet radio and webcasts that can be accessed from anywhere in the world. Some other popular services of the Internet were not created this way, but were originally based on proprietary systems. These include IRC, ICQ, AIM, and Gnutella. There have been many analyses of the Internet and its structure. For example, it has been determined that the Internet IP routing structure and hypertext links of the World Wide Web are examples of scale-free networks. Similar to how the commercial Internet providers connect via Internet exchange points, research networks tend to interconnect into large subnetworks such as:
- GEANT
- Internet2
- GLORIAD These in turn are built around relatively smaller networks. See also the list of academic computer network organizations In network schematic diagrams, the Internet is often represented by a cloud symbol, into and out of which network communications can pass.

Internet culture

The Internet is also having a profound impact on work, leisure, knowledge and worldviews. worldviews]]

ICANN

The Internet Corporation for Assigned Names and Numbers (ICANN) is the authority that coordinates the assignment of unique identifiers on the Internet, including domain names, Internet protocol addresses, and protocol port and parameter numbers. A globally unified namespace (i.e., a system of names in which there is one and only one holder of each name) is essential for the Internet to function. ICANN is headquartered in Marina del Rey, California, but is overseen by an international board of directors drawn from across the Internet technical, business, academic, and non-commercial communities. The US government continues to have a privileged role in approving changes to the root zone file that lies at the heart of the domain name system. Because the Internet is a distributed network comprising many voluntarily interconnected networks, the Internet, as such, has no governing body. ICANN's role in coordinating the assignment of unique identifiers distinguishes it as perhaps the only central coordinating body on the global Internet, but the scope of its authority extends only to the Internet's systems of domain names, Internet protocol addresses, and protocol port and parameter numbers.

The World Wide Web

Through keyword-driven Internet research using search engines like Google, millions worldwide have easy, instant access to a vast and diverse amount of online information. Compared to encyclopedias and traditional libraries, the World Wide Web has enabled a sudden and extreme decentralization of information and data. Some companies and individuals have adopted the use of 'weblogs' or blogs, which are largely used as easily-updatable online diaries. Some commercial organizations encourage staff to fill them with advice on their areas of specialization in the hope that visitors will be impressed by the expert knowledge and free information, and be attracted to the corporation as a result. One example of this practice is Microsoft, via whose product developers publish their personal blogs in order to pique the public's interest in their work. For more information on the distinction between the World Wide Web and the Internet itself — as in everyday use the two are sometimes confused — see Dark internet where this is discussed in more detail.

Remote access

The Internet allows computer users to connect to other computers and information stores easily, wherever they may be across the world. They may do this with or without the use of security, authentication and encryption technologies, depending on the requirements. This is encouraging new ways of working from home, collaboration and information sharing in many industries. An accountant sitting at home can audit the books of a company based in another country, on a server situated in a third country that is remotely maintained by IT specialists in a fourth. These accounts could have been created by home-working book-keepers, in other remote locations, based on information e-mailed to them from offices all over the world. Some of these things were possible before the widespread use of the Internet, but the cost of private, leased lines would have made many of them infeasible in practice. An office worker away from his or her desk, perhaps the other side of the world on a business trip or a holiday, can open a remote desktop session into his or her normal office PC using a secure Virtual Private Network (VPN) connection via the Internet. This gives him or her complete access to all their normal files and data, including e-mail and other applications, while they are away.

Collaboration

This low-cost and nearly instantaneous sharing of ideas, knowledge and skills has revolutionized some, and given rise to whole new, areas of human activity. One example of this is the collaborative development and distribution of Free/Libre/Open-Source Software (FLOSS) such as Linux, Mozilla and OpenOffice.org. See Collaborative software.

File-sharing

A computer file can be e-mailed to customers, colleagues and friends as an attachment. It can be uploaded to a website or FTP server for easy download by others. It can be put into a "shared location" or onto a file server for instant use by colleagues. The load of bulk downloads to many users can be eased by the use of "mirror" servers or peer-to-peer networking. In any of these cases, access to the file may be controlled by user authentication; the transit of the file over the Internet may be obscured by encryption and money may change hands before or after access to the file is given. The price can be paid by the remote charging of funds from, for example a credit card whose details are also passed - hopefully fully encrypted - across the Internet. The origin and authenticity of the file received may be checked by digital signatures or by MD5 message digests. These simple features of the Internet, over a world-wide basis, are changing the basis for the production, sale and distribution of many types of product, wherever they can be reduced to a computer file for transmission. This includes all manner of office documents, publications, software products, music, photography, video, animations, graphics and the other arts. This in turn is causing seismic shifts in each of the existing industry associations, such as the RIAA and MPAA, that previously controlled the production and distribution of these products.

Streaming media and VoIP

Many existing radio and television broadcasters have provided Internet 'feeds' of their live audio and video streams (for example, the BBC). They have been joined by a range of pure Internet 'broadcasters' who never had on-air licences. This means that an Internet-connected device, such as a computer or something more specific, can be used to access on-line media in much the same way as was previously possible only with a TV or radio receiver. The range of material is much wider, from pornography to highly specialised technical web-casts. The simplest equipment can allow anybody, with little censorship or licencing control, to broadcast on a worldwide basis. Time-shift viewing or listening is not a problem as the BBC have shown with their Preview, Classic Clips and Listen Again features. Web-cams can be seen as an even lower-budget extension of this phenomenon. In this case the picture may update only slowly - perhaps once every few seconds or slower, but Internet users can watch animals around an African waterhole, ships in the Panama Canal or the traffic at a local roundabout live and in real time. Video chat rooms, video conferencing, and remote controllable webcams have become popular. Some people install webcams in their bedrooms that can be accessed by other voyeurs, often with two-way sound. VoIP stands for Voice over IP, where IP refers to the Internet Protocol that underlies all Internet communication. This phenomenon began as an optional two-way voice extension to some of the Instant Messaging systems that took off around the turn of the millennium. In recent years many people and organizations have made VoIP systems as easy to use and as convenient as a normal telephone. The benefit is that, as the actual voice traffic is carried by the Internet, VoIP is free or costs much less than an actual telephone call, especially over long distances and especially for those with always-on ADSL or DSL Internet connections anyway. The disadvantages are that it is still difficult to initiate a call with someone, unless they also have a VoIP phone or are at their computer and that there are still several competing standards that are mitigating against universal acceptance. In all of these cases, existing large organisations, that have grown accustomed to regular incomes for their services, are finding increased competition in their service areas, coming directly from the Internet. While newcomers strive to make these inroads, the traditional industries are having to adapt, adopt, complain or suffer. Meanwhile the consumer in each case most probably benefits from the increased range of services and possible price reductions. Some worry about censorship and control while others see a continuing globalisation of culture and norms.

Language

Main article: English on the Internet The most prevalent language for communication on the Internet is English. This may be due to the Internet's origins or to the growing role of English as an international language. It may also be related to the poor capability of early computers to handle characters other than those in the basic Latin alphabet (see Unicode). After English (32 % of web visitors) the most-requested languages on the world wide web are Chinese 13 %, Japanese 8 %, Spanish 6 %, German 6 % and French 4 %. (From [http://www.internetworldstats.com/stats7.htm Internet World Stats]) By continent, 33 % of the world's Internet users are based in Asia, 29 % in Europe and 23 % in North America.[http://www.internetworldstats.com/stats.htm] The Internet's technologies have developed enough in recent years that good facilities are available for development and communication in most widely used languages. However, some glitches such as mojibake still remain.

Cultural awareness

From a cultural awareness perspective, the Internet has been both an advantage and a liability. For people who are interested in other cultures it provides a significant amount of information and an interactivity that would be unavailable otherwise. However, for people who are not interested in other cultures there is some evidence indicating that the Internet enables them to avoid contact to a greater degree than ever before.

Censorship

Some countries, such as Iran and the People's Republic of China, restrict what people in their countries can see on the Internet, especially unwanted political and religious content. In the Western world, it is Germany that has the highest rate of censorship. Internet Service Providers are required by law to block some sites that contain child pornography or Nazi or Islamist propaganda. Censorship is sometimes done through government sponsored censoring filters, or by means of law or culture, making the propagation of targeted materials extremely hard. At the moment most Internet content is available regardless of where one is in the world, so long as one has the means of connecting to it.

Internet access

Germany Common methods of home access include dial-up, landline broadband (over coaxial cable, fiber optic or copper wires), Wi-Fi, satellite and cell phones. Public places to use the Internet include libraries and Internet cafes, where computers with Internet connections are available. There are also Internet access points in many public places like airport halls, in some cases just for brief use while standing. Various terms are used, such as "public Internet kiosk", "public access terminal", and "Web payphone". Many hotels now also have public terminals, though these are usually fee based. Wi-Fi provides wireless access to computer networks, and therefore can do so to the Internet itself. Hotspots providing such access include Wi-Fi-cafes, where a would-be user needs to bring their own wireless-enabled devices such as a laptop or PDA. These services may be free to all, free to customers only, or fee-based. A hotspot need not be limited to a confined location. The whole campus or park, or even the entire city can be enabled. Grassroots efforts have led to wireless community networks. Apart from Wi-Fi, there have been experiments with proprietary mobile wireless networks like Ricochet, various high-speed data services over cellular or mobile phone networks, and fixed wireless services. These services have not enjoyed widespread success due to their high cost of deployment, which is passed on to users in high usage fees. New wireless technologies such as WiMAX have the potential to alleviate these concerns and enable simple and cost effective deployment of metropolitan area networks covering large, urban areas. There is a growing trend towards wireless mesh networks, which offer a decentralized and redundant infrastructure and are often considered the future of the Internet. Broadband access over power lines was approved in 2004 in the United States in the face of stiff resistance from the amateur radio community. The problem with modulating a carrier signal onto power lines is that an above-ground power line can act as a giant antenna and jam long-distance radio frequencies used by amateurs, seafarers and others. Countries where Internet access is available to a majority of the population include Germany, India, China, Chile, Iceland, Finland, Sweden, Greece, Italy, Australia, Denmark, the United States, Canada, the United Kingdom, The Netherlands, Japan, Singapore, Taiwan, Thailand, South Korea and Norway. The use of the Internet around the world has been growing rapidly over the last decade, although the growth rate seems to have slowed somewhat after 2000. The phase of rapid growth is ending in industrialized countries, as usage becomes ubiquitous there, but the spread continues in Africa, Latin America, the Caribbean and the Middle East. However, there are still problems for many. ADSL and other broadband access are rare or nonexistent in most developing countries. Even in developed countries, high prices, mediocre performance and access restrictions often limit its uptake. Within individual countries, wide differences may exist between larger cities (often having multiple providers of broadband access) and some rural areas, where no broadband access may be available at all. The expansion of the availability of Internet access is a way to bridge the so-called digital divide.

Capitalization conventions

In formal usage, Internet is traditionally written with a capital first letter. The Internet Society, the Internet Engineering Task Force, the Internet Corporation for Assigned Names and Numbers, the World Wide Web Consortium, and several other Internet-related organizations all use this convention in their publications. In English grammar, proper nouns are capitalized. Most newspapers, newswires, periodicals, and technical journals also capitalize the term. Examples include the New York Times, the Associated Press, Time, The Times of India, Hindustan Times and Communications of the ACM. In other cases, the first letter is often written small (internet), and many people are not aware of any convention of using a capital letter. Some argue that internet is the correct form. Since 2000, a significant number of publications have switched to using internet. Among them are The Economist, the Financial Times, the London Times, and the Sydney Morning Herald. As of 2005, most publications using internet appear to be located outside of North America although one American news source, Wired News, has adopted the lowercase spelling.

Leisure

The Internet has been a major source of leisure since before the World Wide Web, with entertaining social experiments such as MOOs being conducted on university servers, and humor-related USENET groups receiving much of the main traffic. Today, many Internet forums have sections devoted to neta; short cartoons in the form of Flash movies are also popular. The pornography and gambling industries have both taken full advantage of the World Wide Web, and often provide a significant source of advertising revenue for other Web sites. Although many governments have attempted to put restrictions on both industries' use of the Internet, this has generally failed to stop their widespread popularity. One main area of leisure on the Internet is multiplayer gaming. This form of leisure creates communities, bringing people of all ages and origins to enjoy the fast-paced world of multiplayer games. These range from MMORPG to first-person shooters, from role-playing games to online gambling. This has revolutionized the way many people interact and spend their free time on the Internet. Online gaming began with services such as GameSpy and MPlayer, which players of games would typically subscribe to. Non-subscribers were limited to certain types of gameplay or certain games. With the release of Diablo by Blizzard Entertainment, gamers were treated to a built in online game service that was free of charge. With Blizzard's next game, StarCraft, the gaming world saw an explosion in the numbers of players using the Internet to play multi-player games. StarCraft may have been the first non-MMO game in which most players utilized the online gameplay as opposed to the single-player gameplay. Online gaming has progressed so much in the last 10 years that gamers earn a living from being a professional at the subject by winning tournaments and prizes as well as signing sponsor deals. Because there is a large support for certain online games, a new community has been born for people modding games, where users edit games to add a whole new element to it. This is how games such as Counter-Strike were born from the Half-Life Gaming Engine. Cyberslacking has become a serious drain on corporate resources; the average UK employee spends 57 minutes a day surfing, according to a study by Peninsula Business Services[http://news.scotsman.com/topics.cfm?tid=914&id=1001802003].

A complex system

Many computer scientists see the Internet as a "prime example of a large-scale, highly engineered, yet highly complex system" (Willinger, et al). The Internet is extremely heterogeneous. (For instance, data transfer rates and physical characteristics of connections vary widely.) The Internet exhibits "emergent phenomena" that depend on its large-scale organization. For example, data transfer rates exhibit temporal self-similarity.

Marketing

The Internet has also become a big market, and the biggest companies today have grown by taking advantage of the efficient low-cost advertising and commerce through the Internet. It is the fastest way to spread information to a vast community of people all at once. The Internet has revolutionized shopping –– a person can order a CD online and receive it in the mail within a couple of days, or download it directly in some cases.

Criticism

Many hyperlinks are outdated as time takes its toll on the existence of URL weblinks. These weblinks are often times defunct and are retained as hyperlinks for extended timeframes as a result of laziness or being busy enough to be sidetracked away from updating webpages. This is a common hoax for people who are fans in the field of what those links provide them with/to.

External links

General

- [http://www.channel101.com/ Internet TV Stations]
- [http://www.isoc.org/ The Internet Society (ISOC)]
- [http://www.techterms.org/internet.php Internet Dictionary] - Definitions of Internet-related terms
- [http://www.experienced-people.co.uk/1099-webmaster-glossary/ The Alternate Internet Glossary] (Humor)
- A [http://www.illusivecreations.com Calgary Web Design] company that has put together over 300 articles about the internet and web development. You can view them by going [http://www.illusivecreations.com/articles/ here].
- [http://www.clickz.com/stats/sectors/geographics/article.php/5911_151151 Internet access stats]
- [http://www.sharpened.net/glossary/ Glossary of Computer and Internet Terms]
- [http://scoreboard.keynote.com/scoreboard/Main.aspx?Login=Y&Username=public&Password=public Internet Health Report] from Keynote
- [http://www.internetworldstats.com/stats.htm Internet World Stats]

Articles

- [http://www.iht.com/articles/2005/09/29/business/net.php "EU and U.S. clash over control of the Net" - International Herald Tribune article by Tom Wright]
- [http://www.wired.com/wired/archive/13.08/intro.html "10 Years that changed the world" - WiReD looks back at the evolution of the Internet over last 10 years]
- [http://www.fourmilab.ch/documents/digital-imprimatur/ John Walker: The Digital Imprimatur]
- [http://www.addressingtheworld.info addressingtheworld.info] - website accompanying a book (ISBN 0742528103) on the history of DNS
- [http://computer.howstuffworks.com/internet-infrastructure.htm How Stuff Works explanation of the Infrastructure of the Internet]
- [http://www.searchandgo.com/articles/internet/net-explained-1.php Internet Explained] Seven part article explaining the origins to the present and a future look at the Internet.
- [http://www.wired.com/news/culture/0,1284,64596,00.html?tw=wn_tophead_7 "It's Just the 'internet' Now" - Wired.com article by Tony Long]

History

- [http://www.isoc.org/internet/history/brief.shtml The Internet Society History Page]
- [http://www.internetvalley.com/archives/mirrors/cerf-how-inet.txt How the Internet Came to Be]
- [http://www.zakon.org/robert/internet/timeline/ Hobbes' Internet Timeline v7.0]
- [http://www.ciolek.com/PAPERS/e-scholarship2000.html Futures and Non-futures for Scholarly Internet. ]
- [http://www.lk.cs.ucla.edu/internet_history.html History of the Internet links]
- [http://www.ietf.org/rfc/rfc801.txt RFC 801, planning the TCP/IP switchover]
- [http://www.archive.org/ Internet Archive] - A searchable database of old cached versions of websites dating back to 1996
- A list of lectures, some of which relate to the Internet, from the Massachusetts Institute of Technology is available [http://ocw.mit.edu/OcwWeb/Comparative-Media-Studies/CMS-930Media--Education--and-the-MarketplaceFall2001/VideoLectures/index.htm here]. Of particular interest is lecture #3 The Next Big Thing: Video Internet which is delivered in Real Player format. The lecture gives a brief history of networking; discusses convergence between the internet/telephone/television networks; the expansion of broadband access; makes predictions about the future of delivery of video over the internet.

References

- Walter Willinger, Ramesh Govindan, Sugih Jamin, Vern Paxson, and Scott Shenker. (2002). Scaling phenomena in the Internet. In Proceedings of the National Academy of Sciences, 99, suppl. 1, 2573 – 2580. Category:Communication Category:Digital media Category:Internet Category:Digital Revolution Category:Technology Category:Computer networks Category:Networks ko:인터넷 ms:Internet ja:インターネット simple:Internet th:อินเทอร์เน็ต fiu-vro:Internet

Top-level domain

A top-level domain (TLD) is the last part of an Internet domain name; that is, the letters which follow the final 'dot' of any URL. For example, in the domain name wikipedia.org, the top-level domain is org (or ORG, as domain names are not case-sensitive). The Internet Assigned Numbers Authority (IANA) currently classifies top-level domains into three types:
- country code top-level domains (ccTLD): Used by a country or a dependent territory. It is two letters long, for example jp for Japan.
- generic top-level domain (gTLD): Used (at least in theory) by a particular class of organizations (for example, com for commercial organizations). It is three or more letters long. Most gTLDs are available for use worldwide, but for historical reasons gov and mil are restricted to the government and military, respectively, of the USA.
- infrastructure top-level domain: The top-level domain arpa is the only one. A full list of currently existing TLDs can be found at the list of Internet top-level domains.

Historical TLDs

A nato TLD was added in the late 1980s by the NIC for the use of NATO, who felt that none of the then existing TLDs adequately reflected their status as an international organization. Soon after this addition, however, the NIC created the int TLD for the use of international organizations, and convinced NATO to use nato.int instead. However, the nato TLD, although no longer used, was not deleted until July 1996. In the past the Internet was just one of many wide-area computer networks. Computers not connected to the Internet, but connected to another network such as Bitnet or UUCP, could generally exchange e-mail with the Internet via e-mail gateways. When used on the Internet, addresses on these networks were often placed under pseudo-domains such as bitnet and uucp; however these pseudo-domains were not real top-level domains and did not exist in DNS. Most of these networks have long since ceased to exist, and although UUCP still gets significant use in parts of the world where Internet infrastructure has not yet become well-established, it subsequently transitioned to using Internet domain names, so pseudo-domains now largely survive as historical relics.

Reserved TLDs

RFC 2606 reserves the following four top-level domain names for various purposes, with the intention that these should never become actual TLDs in the global DNS:
- example — reserved for use in examples
- invalid — reserved for use in obviously invalid domain names
- localhost — reserved to avoid conflict with the traditional use of localhost
- test — reserved for use in tests

TLDs in alternative roots

Alternative DNS roots have their own sets of TLDs. See that article for details.

References

- Addressing the World: National Identity and Internet Country Code Domains, edited by Erica Schlesinger Wass (Rowman & Littlefield, 2003, ISBN 0742528103) [http://www.addressingtheworld.info], examines connections between cultures and their ccTLDs.
- Ruling the Root by Milton Mueller (MIT Press, 2001, ISBN 0262134128) [http://mitpress.mit.edu/catalog/item/default.asp?sid=5BA098F1-E04D-4D4D-98EE-4BF1DDA75B9C&ttype=2&tid=8809], discusses TLDs and domain name policy more generally. Category:Domain Name System Category:Internet governance IANA Category:Top-level domains ko:최상위 도메인 ja:トップレベルドメイン th:โดเมนระดับบนสุด

Domain name registry

In the domain name system on the Internet there is a need for databases to be kept of which domain name maps to which IP address. A registry has two main tasks: # giving out domain names under their top level domain to those who ask for them; and # making the database of domain name registrations available to the world at large. Registries can only operate if the top level domain they run has been delegated to them by IANA. Hence, there can only be one registry for each top level domain. If there is more than one index, confusion would result (as has happened to a limited extent with the .biz top level domain). The endings of the domain name dictate which organization controls them. In practice, this is the organization that controls the name servers for that domain. Therefore ICANN has de facto control of the overall Domain Name System because it controls the root name servers. Registries make the index available to the world via Whois systems and via their name servers, for the direction of internet traffic. Such systems have to be fully redundant because loss of name servers can affect all internet traffic sent to that domain.

Naming conventions

The final section of the name '.com', '.biz', '.uk', '.de' is called the top-level domain (TLD). Some exhibit no affiliation with a particular country (like .com) and are called generic Top Level Domains (gTLD). These are operated by registrars appointed by ICANN. However, in addition, every country in the world has a two letter code (a country code TLD or ccTLD). These ccTLDs are operated by a range of organizations: some are not-for-profit commercial organisations, others are government departments. Some have signed a contract with ICANN, some have not. These ccTLDs also vary in size: while .com has (at the end of 2003) about 21 million registrations spread over the various registrars, .de has some 6.5 million controlled by DENIC (the .de registry) alone and the .uk registry Nominet UK has about 4.5 million. The .ie domain, controlled by IEDR has just over 40,000 entries. Other ccTLDs may have as little as a few hundred. The registry will hold the central register and operate the name servers for that domain. They will generally set policies for the names it controls: it may restrict certain names for political, religious, historical or local legal reasons. Equally, ccTLD registries set the dispute policies for their names: those that have signed up with ICANN generally have to use the UDRP, while Denic require people to use the normal German civil courts, and Nominet UK deal with Intellectual Property and other disputes through its specific dispute resolution service. The ccTLD registries can also control whether matters of interest to their local communities are intruduced: for example, the Japanese and Polish registries have introduced internationalized domain names to allow use of local non-ASCII characters. In the gTLD system there are not really any unified registries in the same way, although the Public Interest Registry which runs .org is close. In the gTLD system ICANN holds a basic register which records the name, other critical details, and which registrar (agent of the registry) runs that name. The registrar holds the other details like the registrant's telephone number.

Operation of registries

Domain name registries, also known as NIC (Network Information Center) are run in many different ways. Some are government departments (e.g. the registry for the Vatican www.nic.va). Some are co-operatives of internet service providers (such as DENIC www.nic.de) or not-for profit companies (such as Nominet UK www.nic.uk). Others are commercial organizations, such as the US registry (www.nic.us). For certain repressive countries, control over the registry and ISPs can effectively control entirely what access their citizens have to the Internet. Domain name registries operate all sorts of systems in order to hand out names. Generally domain name registries operate a first-come-first-served system of allocation. Some registries sell the names directly and others rely on ISPs or registrars to sell them. All registries will have rules about which domain names can be registered. Some of these rules are technical, and so universal, but many are cultural, or depend on the nature of the registry. For example, registries differ hugely in their attitude to obscene or libellous domain names. In the United States, the InterNIC organization handled domain distribution prior to ICANN, and between 1996 and 1998, automatically rejected domain name applications containing words from a list of select obscenities. The level of charges depends on the nature of the Registry - commercial registries naturally tend to charge what the market will bear, whereas non-commercial registries tend to charge less. Domain name registries may also impose a system of second level domains on users. The argument for such domains is that it allows more space and certainty in the system. Thus, for example, governmental organisations cannot be impersonated and individuals can have a domain name that differs from that given to companies. The argument against is that it leads to less memorable names and fragments the system. The contrasting approach can be seen in three of Europe's biggest registries. For example, DENIC, the registry for Germany (.de) does not impose second level domains. AFNIC, the registry for France (.fr) has some second level domains, but not all registrants have to use them, and Nominet UK, the registry for the United Kingdom (.uk) requires all names to have a second level domain.

United Kingdom

:For other meanings of the terms "United Kingdom" and "UK" , see United Kingdom (disambiguation) and UK (disambiguation). :For an explanation of terms like England, (Great) Britain and United Kingdom see British Isles (terminology). The United Kingdom of Great Britain and Northern Ireland (usually shortened to the United Kingdom or the UK) is a country located off the north-western coast of continental Europe, surrounded by the North Sea, the English Channel, the Celtic Sea, the Irish Sea, and the Atlantic Ocean. It is composed of four constituent parts: three constituent countries—England, Scotland, and Wales—on the island of Great Britain, and the province of Northern Ireland on the island of Ireland. The border between Northern Ireland and the Republic of Ireland forms the United Kingdom's principal international land border, although there is a nominal frontier with France in the middle of the Channel Tunnel. The UK has several overseas territories and the Crown dependencies of the Isle of Man and the Channel Islands come under the UK's sovereignty. The UK also has close relationships with the fifteen other Commonwealth Realms, as they all share the same head of state. The UK is also one of the largest member states of the European Union and a founding partner of both the UN and NATO.
Terminology

- United Kingdom of Great Britain and Northern Ireland: The official name for the sovereign state
- United Kingdom: an abbreviation of United Kingdom of Great Britain and Northern Ireland
- Britain: an informal term that sometimes means United Kingdom of Great Britain and Northern Ireland and sometimes means Great Britain
- British: an informal term that sometimes means from the United Kingdom of Great Britain and Northern Ireland and sometimes means from Great Britain
- Great Britain (as a geographical term): the largest island of the British Isles
- Great Britain (as a political term): England + Wales + Scotland
- British Isles (as a geographical term): Great Britain + Ireland + many smaller surrounding islands. This term is disputed, please see below.
- Ireland (as a geographical term): the second largest island of the British Isles
- Ireland (as a political term): an abbreviation of the Republic of Ireland, a sovereign state on the island of Ireland
- Northern Ireland: a political region of the United Kingdom of Great Britain and Northern Ireland
- Ulster (as a geographical term): Often used to refer to Northern Ireland. It is derived from the Irish Language term 'Ulad.' It was one of the ancient Irish provinces (the others were Connaught, Leinster and Munster.). Although it is normally used to refer to Northern Ireland, Ulster also (traditionally) includes Counties Cavan, Monaghan and Donegal, which lie in the Republic of Ireland. The term Ulster is often favoured by the Protestant community.
History
Protestant Today's state is the latest of several unions formed over the last 1000 years. Scotland and England have existed as separate unified entities since the 10th century. Wales, under English control since the Statute of Rhuddlan in 1284, became part of the Kingdom of England by the Laws in Wales Act 1535. With the Act of Union 1707, the separate kingdoms of England and Scotland, having shared the same monarch since 1603, agreed to a permanent union as the Kingdom of Great Britain. The Act of Union 1800 united the Kingdom of Great Britain with the Kingdom of Ireland, which had been gradually brought under English control between 1169 and 1691, to form the United Kingdom of Great Britain and Ireland. The United Kingdom of Great Britain and Northern Ireland was formed in 1922, after bitter fighting which echoes down to the current political strife, the Anglo-Irish Treaty partitioned Ireland into the Irish Free State and Northern Ireland, with the latter remaining part of the United Kingdom. As provided for in the treaty, Northern Ireland, which consists of six of the nine counties of the Irish province of Ulster, immediately opted out of the Free State and to remain in the UK. The nomenclature of the UK was changed in 1927 to recognise the departure of most of Ireland, with the current name being adopted. 1927 The United Kingdom, the dominant industrial and maritime power of the 19th century, played a leading role in developing Western world ideas of property, liberty, capitalism and parliamentary democracy - to say nothing of its part in advancing world literature and science. At its zenith, the British Empire stretched over one quarter of the Earth's surface and encompassed a third of its population. The first half of the 20th century saw the UK's strength seriously depleted from the effects of World War I and World War II. The second half witnessed the dismantling of the Empire and the UK rebuilding itself into a modern and prosperous nation. The UK has been a member of the European Union since 1973. Its attitude towards further integration is conservative, and there is significant Euroscepticism in UK politics. It has not chosen to adopt the Euro, owing to internal political considerations and the government's judgement of the prevailing economic conditions.
Government and politics
The United Kingdom is a constitutional monarchy, with executive power exercised on behalf of the Queen by the Prime Minister and other cabinet ministers who head departments. The cabinet, including the Prime Minister, and other ministers collectively make up Her Majesty's Government. These ministers are drawn from and are responsible to Parliament, the legislative body, which is traditionally considered to be "supreme" (that is, able to legislate on any matter and not bound by decisions of its predecessors). The UK is one of the few countries in the world today that does not have a codified constitution, relying instead on customs and separate pieces of constitutional law. While the monarch is Head of State and holds all executive power, it is the Prime Minister who is the head of government. The government is answerable chiefly to the House of Commons and the Prime Minister is drawn from this chamber of Parliament by constitutional convention. The majority of cabinet members will be from the House of Commons, the rest from the House of Lords. Ministers do not, however, legally have to come from Parliament, though that is the modern day custom. The British system of government has been emulated around the world - a legacy of the United Kingdom's colonial past - most notably in the other Commonwealth Realms. The Prime Minister is chosen as the MP who can command a majority in the House of Commons - usually the leader of the largest party or, if there is no majority party, the largest coalition. The current Prime Minister is Tony Blair of the Labour Party, who has been in office since 1997. In the United Kingdom the monarch has extensive theoretical powers, but his or her role is mainly, though not exclusively, ceremonial. The monarch is an integral part of Parliament (as the "Crown-in-Parliament") and theoretically gives Parliament the power to meet and create legislation. An Act of Parliament does not become law until it has been signed by the Queen (being given Royal Assent), although no monarch has refused to assent to a bill that has been approved by Parliament since Queen Anne in 1708. Although the abolition of the monarchy has been suggested several times, the popularity of the monarchy remains strong in spite of recent controversies. Support for a British republic usually fluctuates between 15% and 25% of the population, with roughly 10% undecided or indifferent [http://www.mori.com/mrr/2000/c000616.shtml]. The current monarch is Queen Elizabeth II who acceded to the throne in 1952 and was crowned in 1953. Parliament is the national legislature of the United Kingdom. It is the ultimate legislative authority in the United Kingdom, according to the doctrine of parliamentary sovereignty. It is bicameral, composed of the elected House of Commons and the unelected House of Lords, whose members are mostly appointed. The House of Commons is the more powerful of the two houses. The House of Commons has 646 members who are directly elected from single-member constituencies based on population. The House of Lords has 724 members (though this number is not fixed): hereditary peers, life peers, and bishops of the Church of England. The Church of England is the established church of the state in England. established church]] The two largest political parties are the Labour Party and Conservative Party. The UK has long had a two-party system, but in the last 20 years the Liberal Democrats have re-emerged as a large third party. The electoral system used for general elections is first-past-the-post. The constitution of the United Kingdom is un-codified and partially unwritten, which means that no single document regulates how the government works, and unwritten constitutional conventions are used extensively. The constitution is based on the principle that Parliament is the ultimate sovereign body in the country. There has long been a widespread sense of national identity in the Celtic nations. Throughout the late 19th century the UK debated giving Ireland home rule. The Scottish National Party was founded in 1934, and Plaid Cymru (Party of Wales) in 1925. Referenda for devolution succeeded in 1997 for Scotland and Wales and in 1998 for Northern Ireland. In 1999, the Scottish Parliament and the National Assembly for Wales were established, the former having primary legislative power. Proportional representation is used for the elections, which has resulted in a Labour-Liberal Democrat coalition government in Scotland. Due to internal disagreements, the Northern Ireland Assembly has been suspended since 2002.
Subdivisions
The United Kingdom is a country that is divided into four constituent parts:
- England
- Scotland
- Northern Ireland
- Wales The constituent parts of the United Kingdom have administrative subdivisions as follows:
- The regions and administrative counties of England
- The council areas of Scotland
- The counties and county boroughs of Wales
- The districts of Northern Ireland The Laws in Wales Act 1535 incorporated Wales and England into England and Wales for legal purposes. Although all four have historically been divided into counties, England's population is an order of magnitude larger than the others so in recent years it has for some purposes been divided into nine intermediate-level Government Office Regions. Each region is made up of counties and unitary authorities, apart from London, which consists of London boroughs. Although at one point it was intended that each or some of these regions would be given its own regional assembly, the plan's future is uncertain, as of 2004, after the North East region rejected its proposed assembly in a referendum. Scotland consists of 32 Council Areas. Wales consists of 22 Unitary Authorities, styled as 10 County Boroughs, 9 Counties, and 3 Cities. Northern Ireland is divided into 26 Districts. Also sometimes associated with the United Kingdom, though not constitutionally part of the United Kingdom itself, are the Crown dependencies (the Bailiwicks of Jersey and Guernsey, and the Isle of Man) as self-governing possessions of the Crown, and a number of overseas territories under the sovereignty of the United Kingdom.
Military
The armed forces of the United Kingdom are known as the British Armed Forces or Her Majesty's Armed Forces, officially the Armed Forces of the Crown. Their Commander-in-Chief is the Queen and they are managed by the Ministry of Defence. Ministry of Defence The British Armed Forces are charged with protecting the United Kingdom and its overseas territories, promoting the United Kingdom's wider security interests, and supporting international peacekeeping efforts. They are active and regular participants in NATO and other coalition operations. The United Kingdom fields one of the most powerful and comprehensive military forces in the World. Its global power projection capabilities are second only to those of the United States Armed Forces. The British Army had a reported strength of 112,700 in 2004, including 7,600 women, and the Royal Air Force a strength of 53,400. The 40,900-member Royal Navy is in charge of the United Kingdom's independent strategic nuclear arm, which consists of four Trident Ballistic Missile Submarines, while the Royal Marines provide infantry units for amphibious assault and for specialist reinforcement forces in and beyond the NATO area. This puts total active duty military troops in the 210,000 range, currently deployed in over 80 countries. The UK's special forces, principally the SAS, provides elite commandos trained for quick, mobile, military responses; often where secrecy or covert operations are required. The Royal Navy is the second largest navy in the World in terms of gross tonnage. Despite the United Kingdom's wide ranging capabilities, recent pragmatic defence policy has a stated assumption that any large operation would be undertaken as part of a coalition. Bosnia, Kosovo, Afghanistan, Iraq (Granby, No-Fly-Zones, Desert Fox and Telic) may all be taken as precedent - indeed the last true war in which the British military fought alone was the Falklands War of 1982, in which military action was initiated by Argentina and the UK was fighting a defensive, rather than offensive, campaign. The British army has been actively involved in the Troubles in Northern Ireland. However, a programme of demilitarisation is being gradually implemented.
Geography
Troubles World Factbook Map of the United Kingdom]] Most of England consists of rolling lowland terrain, divided east from west by more mountainous terrain in the Northwest (Cumbrian Mountains of the Lake District) and north (the upland moors of the Pennines) and limestone hills of the Peak District by the Tees-Exe line. The lower limestone hills of the Isle of Purbeck, Cotswolds, Lincolnshire and chalk downs of the Southern England Chalk Formation. The main rivers and estuaries are the Thames, Severn and the Humber Estuary. The largest urban area is Greater London. Near Dover, the Channel Tunnel links the United Kingdom with France. There is no peak in England that is 1000 metres (3,300 ft) or greater. Wales is mostly mountainous, the highest peak being Snowdon at 1085 metres (3,560 ft) above sea level. North of the mainland is the island of Anglesey. The largest and capital city is Cardiff, located in South Wales. Scotland's geography is varied, with lowlands in the south and east and highlands in the north and west, including Ben Nevis, the UK's highest mountain at 1343 metres (4,406 ft). There are many long and deep-sea arms, firths, and lochs. A multitude of islands west and north of Scotland are also included, notably the Hebrides, Orkney Islands and Shetland Islands. The largest city is Glasgow. Northern Ireland, making up the north-eastern part of Ireland, is mostly hilly. The main cities are Belfast ('Beal Feirste' in Irish) and Londonderry / Derry ('Doire' in Irish). The province is home to one of the UK’s World Heritage Sites, the Giant's Causeway, which consists of more than 40,000 six-sided basalt columns up to 40 feett (12 m) high. In total it is estimated that the UK includes around 1098 small islands, some being natural and some being crannogs, a type of artificial island which was built in past times using stone and wood, gradually enlarged by natural waste building up over time.
Economy
artificial island The United Kingdom, a leading trading power and financial centre, has an essentially capitalist economy, the fourth largest in the world in terms of market exchange rates and the sixth largest by purchasing power parity (PPP) exchange rates. Over the past three decades, the government has greatly reduced public ownership by means of privatisation programmes, and has contained the growth of the Welfare State. Agriculture is intensive, highly mechanised, and efficient by European standards, producing about 60% of food needs with only 1% of the labour force. The UK has large coal, natural gas, and oil reserves; primary energy production accounts for 10% of GDP, one of the highest shares of any industrial state. Services, particularly banking, insurance and business services, account for by far the largest proportion of GDP. Industry continues to decline in importance, although the UK is still Europe's largest manufacturer of armaments, petroleum products, personal computers, televisions, and mobile telephones. Tourism is also important: with over 24 million tourists a year, between China (33) and Austria (19.1), the United Kingdom is ranked as the sixth major tourist destination in the world. The Blair government has put off the question of participation in the Euro system, citing five economic tests that would need to b