Introduced | January 1, 1985 |
---|---|
TLD type | Infrastructure domain |
Status | Active |
Registry | IANA |
Sponsor | Internet Architecture Board |
Intended use | A temporary TLD to facilitate the transition from ARPANET to the DNS. |
Actual use | Internet infrastructure such as reverse DNS lookup. |
Registration restrictions | No domain registrations possible, new subdomains rarely added |
Structure | Second-level domains used for various functions related to Internet infrastructure as defined by RFCs. |
Documents | RFC 3172; RFC 9120 |
Dispute policies | None |
DNSSEC | Yes |
Registry website | IANA .arpa info |
The domain name arpa is a top-level domain (TLD) in the Domain Name System (DNS) of the Internet. It is used predominantly for the management of technical network infrastructure. Prominent among such functions are the subdomains in-addr.arpa and ip6.arpa, which provide namespaces for reverse DNS lookup of IPv4 and IPv6 addresses, respectively.
The name originally was the acronym for the Advanced Research Projects Agency (ARPA), the funding organization in the United States that developed the ARPANET, the precursor of the Internet. It was the first domain defined for the network in preparation for a hierarchical naming system for the delegation of authority, autonomy, and responsibility. It was originally intended only to serve in a temporary function for facilitating the systematic naming of the ARPANET computers. However, it became practically difficult to remove the domain after infrastructural uses had been sanctioned. As a result, the name was redefined as the backronym Address and Routing Parameter Area.
Domain-name registrations in arpa are not possible, and new subdomains are infrequently added by the Internet Engineering Task Force.
Each computer using the Internet Protocol is identified by a numerical IP address for identification and location addressing. [1] Each host is also assigned a more memorable hostname, which often relates to the purpose or ownership of the host, and is used more conveniently in user interaction with network functions, such as when connecting to or accessing a resource. Originally, the mapping between names and addresses was a cumbersome mechanical process using lookup tables distributed as computer files between network administrators. The Domain Name System (DNS) solved this inefficiency by automating the lookup function with a hierarchical naming system using domain names. When a user requests a network service using a domain name, the protocol implementation (protocol stack) translates the name to an address that can be used to reach a remote host.
This naming function, often called forward resolution, was the original purpose of the top-level domain "ARPA". It was the first domain defined in the first naming system of the nascent Internet, [2] and was supposed to be an initial container domain for all then-existing ARPANET hosts. The next stage of development of the naming architecture foresaw the establishment of specific domains for other purposes based on certain requirements. [2]
In many applications the reverse of the name-to-address mapping is also required. The host receiving a service request may require the domain name of the originating computer, for example, to customize the service, or for verification purposes. This latter function, called Reverse DNS lookup, is implemented in the major uses of the domain arpa: its subdomains in-addr.arpa for Internet Protocol version 4, and ip6.arpa for IPv6.
Conceptually similar lookup and mapping functionality is provided by other subdomains of arpa for specific types of data.
The domain e164.arpa provides a lookup function that retrieves information associated with telephone numbers through the ENUM service. This service may be used to obtain the name of a computer that is capable of routing telecommunication requests for a registered telephone number, or obtain an email address to contact the subscriber of a specific telephone number.
The domain name home.arpa was reserved by the Internet Engineering task force in May 2018 as a special-use domain name for non-unique DNS services in residential networking, to avoid the use of the top-level domain home., which would require DNSSEC signatures. [3] In addition, the use of home. led to domain name leakage to the Internet root name servers. The authoritative name servers for home.arpa intercept locally unresolved queries for the domain and return addresses for certain blackhole servers.
The ARPANET, named for the Advanced Research Projects Agency (ARPA), was launched in 1969, and is considered the earliest predecessor of the Internet. The agency's name was adopted as the name for the first formal name space of the network after it had transitioned to TCP/IP networking in January 1983. [2] The name was used as a naming suffix for all then-existing ARPANET hosts. Hierarchical domain-style names were intended to support delegation of responsibility and authority for adding future hosts to the network.
With the formal development of such a hierarchical naming system, the domain also became one of the inaugural members of a set of domain names for specific types of network members, namely com for commercial users, org for organizations, edu for educational institutions, gov for government entities, and mil for networks of the United States military. [4]
It was expected that the use of arpa would be temporary and that the existing systems would be migrated to other domains. [4] But arpa also provided e-mail addresses associated with the Network Information Center, which administered the naming system. After serving the transitional purpose, it proved impractical to remove the domain. The domain in-addr.arpa had been installed for reverse DNS lookup of IP addresses. [5]
Originally, the IETF intended that new infrastructure databases would be created in the top-level domain int. In May 2000, this policy was reversed and it was decided that the top-level domain int should be restricted to use by international organizations. [6] Arpa was retained for its long-standing purpose, but its full name was changed to the Address and Routing Parameter Area, making the zone name a backronym. [7] Registrations of internet infrastructure services in .int made prior to this policy change, were optionally grandfathered in and not required to move to .arpa.
In March 2010, zone arpa was secured with digital signatures within the Domain Name System Security Extensions (DNSSEC). [8]
Subdomains of arpa are created by resolution in the work groups of the Internet Engineering Task Force via the Request for Comments process, and are maintained by the Internet Assigned Numbers Authority (IANA). The DNS zone arpa has the following subdomains: [9] [10]
Domain | Purpose | Authority document (RFC) |
---|---|---|
6tisch.arpa | For IPv6 over the Time Slotted Channel Hopping mode of IEEE 802.15.4 | RFC 9031 |
as112.arpa | Sinking of DNS traffic for reverse IP address resolutions, misc. | RFC 7535 |
e164.arpa | Mapping of E.164 numbers to Internet URIs | RFC 6116 |
eap-noob.arpa | For the Nimble Out-Of-Band authentication method of the Extensible Authentication Protocol framework | RFC 9140 |
home.arpa | Residential networking | RFC 8375 |
in-addr.arpa | Mapping of IPv4 addresses to domain names | RFC 1035 |
ip6.arpa | Mapping of IPv6 addresses to domain names | RFC 3152 |
in-addr-servers.arpa | Domains for authoritative DNS servers for the reverse lookup domains | RFC 5855 |
ip6-servers.arpa | ||
ipv4only.arpa | Detection of DNS64 availability and NAT64 prefix | RFC 7050 |
iris.arpa | Locating Internet registry information services | RFC 4698 |
ns.arpa | Domain for hosting authoritative DNS servers for the .arpa domain | RFC 9120 |
resolver.arpa | Domain for discovery of designated DNS resolvers | RFC 9462 |
uri.arpa | Resolution of URIs and URNs, according to the Dynamic Delegation Discovery System | RFC 3405 |
urn.arpa | ||
The Domain Name System (DNS) is a hierarchical and distributed naming system for computers, services, and other resources in the Internet or other Internet Protocol (IP) networks. It associates various information with domain names assigned to each of the associated entities. Most prominently, it translates readily memorized domain names to the numerical IP addresses needed for locating and identifying computer services and devices with the underlying network protocols. The Domain Name System has been an essential component of the functionality of the Internet since 1985.
The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and the Internet Protocol (IP). Early versions of this networking model were known as the Department of Defense (DoD) model because the research and development were funded by the United States Department of Defense through DARPA.
Stephen D. Crocker is an Internet pioneer. In 1969, he created the ARPA "Networking Working Group" and the Request for Comments series. He served as chair of the board of the Internet Corporation for Assigned Names and Numbers (ICANN) from 2011 through 2017.
A top-level domain (TLD) is one of the domains at the highest level in the hierarchical Domain Name System of the Internet after the root domain. The top-level domain names are installed in the root zone of the name space. For all domains in lower levels, it is the last part of the domain name, that is, the last non empty label of a fully qualified domain name. For example, in the domain name www.example.com, the top-level domain is .com. Responsibility for management of most top-level domains is delegated to specific organizations by the ICANN, an Internet multi-stakeholder community, which operates the Internet Assigned Numbers Authority (IANA), and is in charge of maintaining the DNS root zone.
A name server is a computer application that implements a network service for providing responses to queries against a directory service. It translates an often humanly meaningful, text-based identifier to a system-internal, often numeric identification or addressing component. This service is performed by the server in response to a service protocol request.
In the Internet, a domain name is a string that identifies a realm of administrative autonomy, authority or control. Domain names are often used to identify services provided through the Internet, such as websites, email services and more. As of 2017, 330.6 million domain names had been registered. Domain names are used in various networking contexts and for application-specific naming and addressing purposes. In general, a domain name identifies a network domain or an Internet Protocol (IP) resource, such as a personal computer used to access the Internet, or a server computer.
The Internet Assigned Numbers Authority (IANA) is a standards organization that oversees global IP address allocation, autonomous system number allocation, root zone management in the Domain Name System (DNS), media types, and other Internet Protocol–related symbols and Internet numbers.
InterNIC, known as the Network Information Center (NIC) until 1993, was the organization primarily responsible for Domain Name System (DNS) domain name allocations and X.500 directory services. From its inception in 1972 until October 1, 1991, it was run by the Stanford Research Institute, now known as SRI International, and led by Jake Feinler. From October 1991 until September 18, 1998, it was run by Network Solutions. Thereafter, the responsibility was assumed by the Internet Corporation for Assigned Names and Numbers (ICANN).
A classful network is an obsolete network addressing architecture used in the Internet from 1981 until the introduction of Classless Inter-Domain Routing (CIDR) in 1993. The method divides the IP address space for Internet Protocol version 4 (IPv4) into five address classes based on the leading four address bits. Classes A, B, and C provide unicast addresses for networks of three different network sizes. Class D is for multicast networking and the class E address range is reserved for future or experimental purposes.
The Domain Name System Security Extensions (DNSSEC) are a suite of extension specifications by the Internet Engineering Task Force (IETF) for securing data exchanged in the Domain Name System (DNS) in Internet Protocol (IP) networks. The protocol provides cryptographic authentication of data, authenticated denial of existence, and data integrity, but not availability or confidentiality.
The domain names example.com, example.net and example.org are second-level domain names in the Domain Name System of the Internet. They are reserved by the Internet Assigned Numbers Authority (IANA) at the direction of the Internet Engineering Task Force (IETF) as special-use domain names for documentation purposes. The domain names are used widely in books, tutorials, sample network configurations, and generally as examples for the use of domain names. The Internet Corporation for Assigned Names and Numbers (ICANN) operates web sites for these domains with content that reflects their purpose.
In computer networks, a reverse DNS lookup or reverse DNS resolution (rDNS) is the querying technique of the Domain Name System (DNS) to determine the domain name associated with an IP address – the reverse of the usual "forward" DNS lookup of an IP address from a domain name. The process of reverse resolving of an IP address uses PTR records. rDNS involves searching domain name registry and registrar tables. The reverse DNS database of the Internet is rooted in the .arpa top-level domain.
A DNS zone is a specific portion of the DNS namespace in the Domain Name System (DNS), which a specific organization or administrator manages. A DNS zone is an administrative space allowing more granular control of the DNS components, such as authoritative nameserver. The DNS is broken up into different zones, distinctly managed areas in the DNS namespace. DNS zones are not necessarily physically separated from one another; however, a DNS zone can contain multiple subdomains, and multiple zones can exist on the same server.
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Further, as indicated by DARPA, the arpa TLD string should be given a different expansion such as "Address and Routing Parameter Area" to avoid any implication that DARPA has operational responsibility for the domain.