The Internet is running out of addresses. To get around this problem and a host of others not addressed in the existing Internet Protocol (IPv4), a new revision has been in development for years, called IPv6. Uptake has been slow; it requires upgrading all the routers and devices that make up the Internet. Apple has a few tricks up its sleeve for pushing IPv6 adoption, and many Mac users are already chin deep in the technology without even knowing it. Here's why, and what it means for users on every platform.