Zeroconf, or Zero Configuration Networking, is a set of techniques that automatically creates a usable IP network without configuration or special servers.

This allows inexpert users to connect computers, networked printers, and other network devices and expect a functioning network to be established automatically. Without Zeroconf, a user must either set up special services, like DHCP and DNS, or set up each computer's network settings manually, which may be challenging for non-technical or novice users.

Zeroconf currently provides these services: Choose numeric network addresses for networked devices, (link-local address autoconfiguration) Automatically resolve and distribute computer host names Automatically locate network services, like printing (service discovery)

From wikipedia