# mDNS mDNS (Multicast DNS) is **a protocol that resolves hostnames to IP addresses within small networks**, acting as a zero-configuration service, especially useful when a local DNS server isn't available. It uses multicast communication, allowing devices to discover each other without a central server. - [マルチキャストDNS - Wikipedia](https://ja.wikipedia.org/wiki/マルチキャストDNS) ## Avahi [avahi - mDNS/DNS-SD](https://avahi.org/) Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. This enables you to plug your laptop or computer into a network and instantly be able to view other people who you can chat with, find printers to print to or find files being shared. Compatible technology is found in Apple MacOS X (branded "[Bonjour](https://developer.apple.com/bonjour/)" and sometimes "Zeroconf").