hostnamelocal

hostnamelocal is a special hostname that, when used in DNS queries, typically resolves to the loopback address 127.0.0.1 or the IPv6 loopback address ::1. This behavior is defined in RFC 6762, which specifies the Multicast DNS (mDNS) protocol. The purpose of hostnamelocal is to allow devices on a local network to refer to themselves by a unique, predictable name without relying on a centralized DNS server.

When a device on a local network is configured with a hostname, such as "mycomputer", and this hostname is appended with ".local", it becomes "mycomputer.local". If another device on the same network attempts to resolve "mycomputer.local", mDNS mechanisms will discover the device advertising that name and return its local IP address. This makes it easier for applications and users to access services or other devices on the local network by name rather than by IP address, which can change.

The use of .local for local network name resolution is a convention established by Bonjour (Apple's implementation of mDNS and DNS-SD) and adopted by mDNS in general. It is important to note that hostnamelocal is not a globally resolvable domain name and should not be used for access from outside the local network. It is exclusively for use within a LAN.