Another nice trick of OS X is its use of IPv6, also for its multicast DNS (Bonjour) networking. This means you can have a bonjour session up and running long be

Another nice trick of OS X is its use of IPv6, also for its multicast DNS (Bonjour) networking. This means you can have a bonjour session up and running long before you have an IPv4 address, especially in the absence of a DHCP server. It's what allows plugging a network cable between two macs and immediately start using NFS.