Feb 03, 2011 River of IPv4 addresses officially runs dry
In a ceremony in Miami this morning, the final five blocks of IPv4 addresses were given out to the five Regional Internet Registries that further distribute IP addresses to the far corners of the planet. The five RIRs still have tens of millions of addresses as working inventory, but once those addresses are given out, it's over. Internet Protocol addresses are a prerequisite for all Internet communication—both the sender and the receiver need one. As such, additional addresses are necessary whenever new users are connected to the Internet.

Without access to more IP addresses, service providers are forced to have their customers share an address. For most types of communication, that's a workable solution, but it makes it much harder for two end-users to communicate directly, such as when making a VoIP call, video chatting, or transferring files directly using an instant messaging program, or through a peer-to-peer filesharing system.

A more permanent solution than sharing addresses is the new version of the Internet Protocol: IP version 6 or IPv6. IPv4 addresses in use today are 32 bits long, or up to 12 digits. This allows for a total of 4.3 billion addresses; 3.7 billion of them are usable. IPv6 has 128-bit addresses, which are 39 digits, allowing for an almost unlimited number of addresses. With IPv6, a single home can have billions of addresses, so each Internet-connected device can have its own IP.

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