What is World IPv6 Day?

At 8 p.m. EST on Tuesday, more than 300 organizations, including Google, Facebook, and Yahoo, will test a new way of routing information around the Internet: Internet Protocol version 6 (IPv6). Though the test run will only last 24 hours, participants may learn valuable lessons about how transitioning to IPv6 could affect their sites and their users. Spearheaded by the Internet Society (ISOC), World IPv6 Day is an international, coordinated effort to test this transition. ISOC hopes the effort will also encourage other organizations to adopt IPv6.

What is IPv6?

Each URL has its own Internet Protocol (IP) address. When you type a URL into a browser, a domain name server provides the corresponding IP address. (The IP address for www.technologyreview.com is 69.147.160.210.) IP addresses are assigned to devices such as Web servers, PCs, cell phones, and printers so that these devices can be located and contacted. IPv6 enables many more devices to connect over the Internet.

Safari, Internet Explorer, Chrome, and Firefox browsers support IPv6 and have done so for several years, but some devices, including many popular home routers, aren't yet IPv6-enabled. Devices released as recently as February lack IPv6 support, and some devices need firmware updates to access IPv6-enabled sites.

Why is IPv6 needed?

The Internet has simply outgrown IPv4—the last few addresses were allotted this past February. IPv4 uses 32-bit addresses, which allow about 4.3 billion unique addresses. IPv6 uses 128-bit addresses, which make possible around 340 trillion trillion trillion unique addresses.