.arpa
From Wikipedia, the free encyclopedia
| Introduced | 1985 |
|---|---|
| TLD type | Infrastructure domain |
| Status | Active |
| Registry | IANA |
| Sponsor | Internet Architecture Board |
| Intended use | Address and Routing Parameter Area: Internet infrastructure such as reverse IP lookup. |
| Registration restrictions | No domain registrations possible, new subdomains rarely added |
| Structure | Second-level domains provide special name spaces for database functions |
| Documents | RFC 3172 |
| Dispute policies | None |
| Website | IANA .arpa info |
arpa is an Internet top-level domain (TLD) used exclusively for Internet infrastructure purposes. The name is a backronym for Address and Routing Parameter Area.
The arpa TLD was originally intended to be a temporary domain to facilitate the transition of the ARPANET host naming conventions and the host table distribution methods to the Domain Name System (DNS). The ARPANET was the predecessor to the Internet, established by the United States Department of Defense Advanced Research Projects Agency (ARPA). When the Domain Name System was introduced in 1985, ARPANET host names were initially converted to domain names by adding the arpa domain name label to the end of the host name, separated with a full stop. Domain names of this form were subsequently rapidly phased out by replacing them with domain names under the newly introduced, categorized top-level domains.
After arpa had served its transitional purpose, it proved impractical to remove the domain, because in-addr.arpa was used for reverse DNS lookup for IP addresses. For example, the mapping of the IP address 145.97.39.155 to a host name is obtained by issuing a DNS query for a pointer record of the domain name 155.39.97.145.in-addr.arpa.
At one time, it was intended that new infrastructure databases be created in int. However, in May 2000 this policy was reversed, and it was decided that arpa should be retained for this purpose, and int should be retained solely for the use of international organizations.[1] In accordance with this new policy, arpa now officially stands for Address and Routing Parameter Area (a backronym).
[edit] Second-level domains
- e164.arpa – ENUM lookup mapping telephone numbers into DNS
- in-addr.arpa – reverse DNS lookup for IPv4 addresses
- ip6.arpa – reverse DNS lookup for IPv6 addresses
- iris.arpa – For use in CRISP
- uri.arpa – for dynamic discovery of URI addressing schemes
- urn.arpa – for dynamic discovery of URN addressing schemes
[edit] References
- ^ "IAB Statement on Infrastructure Domain and Subdomains". Archived from the original on 2009-05-11. http://www.webcitation.org/5ghMmXp5G. Retrieved on 2009-05-08.
[edit] External links
- IANA information on .arpa and its subdomains
- Description of in-addr.arpa domain in RFC 1035 (DNS specification)
- RFC 3172 – Management Guidelines & Operational Requirements for the Address and Routing Parameter Area Domain ("arpa")
- RFC 3405 – Dynamic Delegation Discovery System (DDDS) Part Five: URI.ARPA Assignment Procedures
- Zone file analysis
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