I've been writing mDNS and uPNP code this past week. It's kinda fun. I've been using a hacked-up version of pyzeroconf which breaks out the multicast, dns and mdns stuff so that multicast-but-not-zeroconf code can use the same code paths as the zeroconf code. Sample code for doing a basic multi-cast but not mDNS operation is available :) . The mDNS stuff is a little more involved, basically you set up a chain of DNS records: PTR -> SVC -> A and SVC -> TXT and when a client wants to find a service type (PTR) they broadcast the request and anyone who has a PTR for that service-type responds with PTR records (and if they want screwed up hardware to work, the other records too). The samples would be a lot more impressive if we had netifaces installed by default, but they work as long as you specify the IP on which to listen/to which to restrict the multicast.