What is "localhost"

n. (context computing English) The computer being used locally, contrasted with remote computers elsewhere on a network.

In computer networking, localhost is a hostname that means this computer. It is used to access the network services that are running on the host via its loopback network interface. Using the loopback interface bypasses any local network interface hardware.

The local loopback mechanism is useful for testing software during development, independently of any networking configurations. For example, loopback may be used to direct a locally running web browser to http://localhost to display a local html file.

On most computer systems, localhost resolves to the IP address 127.0.0.1, which is the most commonly used IPv4 loopback address, and to the IPv6 loopback address ::1.

The name localhost is also a reserved top-level domain name, set aside to avoid confusion with the definition as a hostname. The IETF standards restrict domain name registrars from assigning the name localhost in registration procedures, such as for second-level domains.

localhost may refer to:

• localhost, the loopback device IP address
• .localhost, a reserved top-level domain name
• Localhost (software), facilitates access to a peer-to-peer virtual file system via the BitTorrent protocol