Avahi

Avahi is an implementation of the DNS Service Discovery and Multicast
DNS specifications for Zeroconf Computing. It uses D-BUS for
communication between user applications and a system daemon. The daemon
is used to coordinate application efforts in caching replies, necessary
to minimize the traffic imposed on networks.

The Avahi mDNS responder is now complete with features, implementing
all MUSTs and the majority of the SHOULDs of the mDNS and DNS-SD RFCs.
It passes all tests in the Apple Bonjour conformance test suite. In
addition, it supports some nifty things, like correct mDNS reflection
across LAN segments.