RFC 3172 (rfc3172) - Page 2 of 8
Management Guidelines & Operational Requirements for the Address and Routing Parameter Area Domain ("arpa")
Alternative Format: Original Text Document
RFC 3172 arpa Guidelines September 2001
The DNS is also capable of supporting a translation in the opposite
direction, from protocol values to the names of service entities.
One approach in using the DNS in this fashion has been to transform
protocol values into a hierarchically structured identifier space,
and then use these transformed protocol value names as a DNS lookup
key into the appropriate DNS name hierarchy. A common use of this
mechanism has been the reverse of the name to address lookup,
allowing for an IPv4 address to be used to look up a matching domain
name. For example, the IP address 128.9.160.55 can be associated
with the domain name "www.iab.org." by creating the DNS entry
55.160.9.128.in-addr.arpa." and mapping this entry, via a DNS PTR
record, to the value "www.iab.org.".
The resolution of protocol objects into service names is used by a
number of applications to associate services with a particular
protocol object. The correct and efficient operation of these
applications is dependent on the correct and efficient operation of
the associated "arpa" domain name servers.
2. The "arpa" domain
The "arpa" domain was originally established as part of the initial
deployment of the DNS, to provide a transition mechanism from the
Host Tables that were common in the ARPANET, as well as a home for
the IPv4 reverse mapping domain. During 2000, the abbreviation was
redesignated to "Address and Routing Parameter Area" in the hope of
reducing confusion with the earlier network name.
The Internet Architecture Board (IAB), in cooperation with the
Internet Corporation for Assigned Names and Numbers (ICANN), is
currently responsible for managing the Top Level Domain (TLD) name
"arpa". This arrangement is documented in Appendix A. This domain
name provides the root of the name hierarchy of the reverse mapping
of IP addresses to domain names. More generally, this domain name
undertakes a role as a limited use domain for Internet
infrastructure applications, by providing a name root for the mapping
of particular protocol values to names of service entities. This
domain name provides a name root for the mapping of protocol values
into lookup keys to retrieve operationally critical protocol
infrastructure data records or objects for the Internet.
The IAB may add other infrastructure uses to the "arpa" domain in the
future. Any such additions or changes will be in accordance with the
procedures documented in Section 2.1 and Section 3 of this document.
Huston Best Current Practice