Editing Top-level domain (section)

==Infrastructure domain==
The domain [[.arpa]] was the first Internet top-level domain. It was intended to be used only temporarily, aiding in the transition of traditional ARPANET host names to the domain name system. However, after it had been used for [[reverse DNS lookup]], it was found impractical to retire it, and is used today exclusively for Internet infrastructure purposes such as in-addr.arpa for [[IPv4]] and ip6.arpa for IPv6 reverse DNS resolution, uri.arpa and urn.arpa for the [[Dynamic Delegation Discovery System]], and e164.arpa for [[telephone number mapping]] based on [[NAPTR record|NAPTR DNS records]]. For historical reasons, [[.arpa]] is sometimes considered to be a generic top-level domain.<ref>{{Cite web |title=.ARPA Domain |url=https://www.iana.org/domains/arpa |access-date=2023-12-16 |website=www.iana.org}}</ref>