.arpa
The domain arpa is a top -level domain in the Domain Name System (DNS) of the Internet. It is used exclusively for technical infrastructure purposes. Although the name was originally an acronym for the Advanced Research Projects Agency (ARPA ), the mining company in the United States, which developed the predecessor of the Internet ( ARPANET ), it now stands for Address and Routing Parameter Area (Address and Routing Parameter area).
Arpa contains, among other, the in-addr.arpa domains and ip6.arpa, which are used in each reverse DNS lookups of IPv4 or IPv6 addresses.
History
The arpa top-level domain was the first domain name system (DNS) was set up in a domain. Originally it was intended as a temporary domain to facilitate the transition of the ARPANET host name conventions on the host table distribution methods of DNA. The ARPANET was the predecessor of the Internet, which was provided by the Advanced Research Projects Agency (ARPA ) of the Department of Defense of the United States. As the domain name system was introduced in 1985, ARPANET host names were initially converted into domain named by the arpa domain label was added to the end of the existing host name, separated by a dot. This form of domain names was then discarded rapidly by being replaced with the newly introduced categorized top- level domains.
After arpa has served his transitional purpose, it turned out that it was impractical to delete the domain, as in-addr.arpa was used for the Inverse DNS search of IP addresses. For example, the assignment of the IP address 145.97.39.155 is accomplished to a host name by a DNS query for a pointer of Domain Names 155.39.97.145.in -addr.arpa is executed.
It was envisaged that new infrastructure databases in the top-level domain will be created int. However, this requirement was lifted in May 2000 and it was decided that arpa is to be maintained for this purpose. int should be used by international organizations. In accordance with this new default arpa now stands ( a backronym ) for Address and Routing Parameter Area.
Second -level domains
- E164.arpa - ENUM to translate telephone numbers into Internet addresses
- In-addr.arpa - Inverted DNS lookups for IPv4 addresses
- Ip6.arpa - Inverted DNS lookups for IPv6 addresses
- Iris.arpa - For the use of Cross Registry Information Service Protocol ( CRISP )
- Uri.arpa - For the dynamic determination of Uniform Resource Identifier ( URI) addressing scheme
- Urn.arpa - For the dynamic determination of Uniform Resource Name ( URN) addressing scheme