IPv4 vs IPv6

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This post is part of a series designed to help developers who are just starting out understand some basics and how they relate to WordPress. This tenth post in the series is about the IP address system, and in particular IPv4 and IPv6 and why knowing about them is important. We’ll walk you through the basics and provide insight into why we can’t just give out IPs like candy.

First, let’s try to understand what IPv4 and IPv6 are. They are simply versions of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and that routes traffic across the Internet. Obvious IPv4 came first and that was in 1981, while IPv6 was finalized around 1998 (but wasn’t commercially deployed until 2006). IPv4, the fourth version of the protocol, as of this summer still carried about 95% of the traffic worldwide, whereas IPv6 had only 5%. Since IPv4 uses 32-bit (four-byte) addresses, this limits the address space to 4,294,967,296 addresses (4.3 billion). That might sound like a lot, but the internet is a big place with lots of demand for IPs, so IPv6 was developed to combat the problem.

IPv6 uses 128-bit addresses, allowing for 340,282,366,920,938,463,463,374,607,431,768,211,456. For math geeks out there that’s a staggering three hundred and forty undecillion, two hundred and eighty-two decillion, three hundred and sixty-six nonillion, nine hundred and twenty octillion, nine hundred and thirty-eight septillion, four hundred and sixty-three sextillion, four hundred and sixty-three quintillion, three hundred and seventy-four quadrillion, six hundred and seven trillion, four hundred and thirty-one billion, seven hundred and sixty-eight million, two hundred and eleven thousand, four hundred and fifty-six. Okay, so we’ve saved the world right? Not so fast!

Since IPv6 isn’t backward compatible with IPv4, we’re still in deep merde as they say in France. This means network operators need to run a dual stack IPv4/IPv6 network for quite a distance into the near future. And for IPv6 to work, it needs to be implemented fully end to end, meaning IPv6 has to be enabled by network hardware vendors, transit providers, access providers, content providers, and endpoint hardware makers. In other words, everyone needs to be on the same page with it. Because upgrades like this cost money and there’s little economic inventive for some of the parties involved, many sat on the sidelines and waited for momentum to build slowly. That’s why IPv6 was finished in 1998, deployed commercially in 2006, and we’re still 95% on IPv4!

Making things worse is that some started using CGN to put the problem off, which is carrier-grade network (CGN) address translation (NAT). This translates private IPs within a carrier’s network to a smaller # of public IPs in much the same way that ordinary NAT lets individuals and companies use multiple internal IPs. However, CGN is not a perfect solution. It’s expensive for carriers and that money might be better spent getting ready for IPv6. Second, the internet’s underpinnings operate on the premise that a single public IP uniquely IDs a carrier subscriber. CGN breaks this logic, which means that it breaks geolocation services and makes life difficult for law enforcement (e.g. FBI, CIA) to identify users behind the curtain. As if that’s not bad enough, some carriers are swapping IPs on an IP Address Black Market of sorts. This means ARIN (American Registry for Internet Numbers) has no idea this occurred and further complicates things.

In summary, IP addresses are in short supply and customers/stakeholders often have a hard time understanding why dedicated IPs cost money or why hosts don’t just give them out. Here at Pagely┬« we are billed by Amazon for each dedicated IP and simply pass that cost along to our customers without significant mark up. Because of the shortage of IPs at Amazon, we can only offer dedicated IPs for Business plans and above, and only if it’s for SSL purposes. Since Matt Cutts at Google has publicly put out many statements that having a dedicated IP is not going to help your SEO, that’s not a good enough reason in our viewpoint. Of course VPS plans and above all come with a free dedicated IP and we’re flexible in that case if you need additional IPs since you’re running your own hardware and likely have valid reasons for needing additional ones.

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