Every available Internet protocol address has now been spoken for—which could mean huge trouble down the line.
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The problem is that the current system for IP addresses, IPv4, uses numeric addresses that are 32 bits long—giving a total of just over four billion potential numbers, which must have seemed like a lot when IPv4 was introduced in 1981. But there are now seven billion people on Earth, and more and more of them—and their devices—are going online all the time. Fortunately, engineers realized the limitations of IPv4 a long time ago and lined up a successor, called IPv6, in 1998.
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For ISPs, it’s a straightforward business dilemma: the two addressing schemes are not directly compatible, which means it would take a significant investment to let IPv4 users connect to IPv6 services. And having relied on the same system for as long as 30 years, they may not feel the need to change.