The name localhost is a commonly defined hostname for the loopback interface in most TCP/IP systems, resolving to the IP addresses 127.0.0.1 in IPv4 and ::1 for IPv6. As a top-level domain, the name has traditionally been defined statically in host DNS implementations with address records (A and AAAA) pointing to the same loopback addresses. Any other use conflicts with widely deployed algorithms relying on this convention.