- .arpa
- Reserved exclusively to support operationally-critical infrastructural identifier spaces as advised by the Internet Architecture Board
Registrar: Internet Assigned Numbers Authority
Infrastructure Top Level Domains (Infrastructure TLDs)
You can find basic top level domain (TLD) information, including ownership, contacts and technical details - nameservers and whois server here. New TLD registrar information for applications in ICANN New gTLDs program are in section New Top Level Domains (TLDs).