Section 5.7. Summary

5.7. Summary

Chapter 4 showed how DNS Service Discovery using Multicast DNS provides a simple, efficient, lightweight way to discover what services of a given type are available to you on the local network. DNS-SD using Unicast DNS takes the same elegant simple concepts and scales literally to the entire planet, using the existing hierarchy of DNS servers that's already in place and well understood at just about all large companies, universities, and other similar organizations around the world.

Dynamic DNS Update Leases provide for automatic garbage collection of stale records. DNS Long-Lived Queries give clients timely notification of information they're interested in. NAT Port Mapping Protocol lets clients behind NAT gateways receive incoming connections. Put these three technologies together with wide-area DNS Service Discovery, and computers at home behind NAT gateways can begin to function like computers connected to the "real" Internet.