View source for TLD .arpa

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| name                   = TLD .arpa
| formattype             = electronic
| subcat                 = Top-level domain
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| released               = 1985
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The top-level domain '''.arpa''' was originally created at the time when the old ARPAnet was transitioning into the Internet, with use of the TCP/IP protocols and DNS to combine a multiplicity of networks into one global network. It was appended to the hostnames of ARPAnet nodes to give them their initial domain address (it was common in those days to informally use domain-style addresses to refer to sites on different networks; [[TLD .uucp|.uucp]] and [[TLD .bitnet|.bitnet]] addresses sometimes appeared even though those domains never existed in the Internet root), to be changed later as the sites acquired more appropriate permanent addresses depending on the type of organization (e.g., [[TLD .edu|.edu]] for educational institutions, [[TLD .gov|.gov]] for government sites, [[TLD .com|.com]] for commercial entities). Once this transition was finished, it was expected that this domain would ultimately be removed as unnecessary. 

However, one of the domains placed in this TLD was <code>in-addr.arpa</code>, used for reverse lookups of IP addresses, and this became a permanent part of the network's infrastructure, preventing the removal of its TLD. Some thought of moving it to [[TLD .int|.int]] was done, but this was decided against; too much software was already hardcoded to use the existing address. Ultimately, the geeks behind the scenes of making the Internet run decided to reposition .arpa as the "Address and Routing Parameter Area", intended specifically for infrastructure elements such as <code>in-addr.arpa</code> and others such as <code>ip6.arpa</code> that were added later. RFC 3172 documented this status.

New second-level domains in .arpa are rarely added, and getting one into the system usually requires proposing a new standard through the RFC process.

==External link==
* [[wikipedia:.arpa]]
* [http://www.iana.org/domains/arpa Official IANA site]