The internet as it was supposed to be
Internet users who want to do more than handle e-mail, browse the web and chat on social media soon run up against issues. Many internet connections rely on IPv4 plus (CG)NAT, a set-up that isn't suitable for hosting your own services or for peer-to-peer communication. With IPv6, the internet works the way it was always supposed to: everyone is reachable again. However, the real benefits of IPv6 are only felt if everyone actually switches over from the old protocol.
The average internet user, who's mainly interested in e-mail, browsing, chatting and social media, is unlikely to see much reason for a proper dual-stack IPv4/IPv6 connection. For the minority who want to do more, however, a partial connection based exclusively on IPv4 quickly proves frustrating. Because what nearly all end users get from their access providers and network administrators is a non-routable IPv4 address behind a NAT system. Meaning that the users aren't directly reachable from the outside world.
Compare the various forms of internet connection, and it's easy to see the shortcomings of the current situation:
Client-server, where the end user's computer/mobile accesses an internet-connected server; examples, as above: mail, browsing, chatting and social media
Reverse client-server, where an internet-connected computer accesses an end user system; examples: running your own web server (self-hosting), remotely accessing your home storage (files, music collection, etc) while out and about, and accessing a self-managed address book, diary, bookmarks, task list or notes from various devices
Peer-to-peer, where two end users' 'clients' communicate directly; examples: real-time interaction in multi-player games, real-time voice and video interaction in VoIP/WebRTC calling, and direct connections between distributed network nodes (e.g. BitTorrent, cryptocurrency networks, Tor and I2P)
Host-to-host, where two internet-connected servers communicate; examples: Usenet news servers and mail servers (MTAs)
The last of those connection forms is not considered further in this article, since the systems involved form part of the internet infrastructure and have their own static IPv4 addresses. They don't therefore communicate directly with end users in this context.
IPv4 address supply ran out long ago
In practice, only the first of the connection forms listed above is actually still available to end users. The reason being the near-ubiquitous use of (Carrier-Grade) NAT to keep extending the life of IPv4: end users' computers can't be accessed directly from the internet, because they no longer have unique IP addresses. Hence the assertion that the supply of IPv4 addresses ran out long ago. The main reason why that hasn't brought the internet to a screeching halt is that all sorts of technical workarounds have been adopted. However, those workarounds are increasingly inadequate and mutually incompatible.
If you pause to think about connection forms 2 and 3, it's easy to see that access providers have a strong commercial incentive to put off the implementation of IPv6 for as long as possible. After all, many access providers are also service and telecom providers, and there's money to be made from selling commercial hosting and expensive conferencing services to internet users who want more than the basics.
To understand how the internet was supposed to work, simply take a look at RFC 1, published exactly fifty years ago this week. You won't find any mention of asymmetric internet connections. The RFC features only hierarchically equal hosts, each with its own unique address and therefore fully accessible.
Alert readers will immediately see that what RFC 1 describes corresponds to connection form 4 in the list above. And that's no coincidence. As things stand, end users have to make do with substandard internet connections, because they don't have their own unique IP addresses. Every host that forms part of the internet infrastructure has its own unique address, for the simple reason that the system couldn't work properly otherwise.
Getting rid of IPv4 and the workarounds
IPv4 and the associated workarounds have had their day. It's high time that end users became fully fledged internet members once more, and that's possible only if we all switch to IPv6. The IPv6 inventory we did last year showed that the Netherlands was lagging well behind on adoption of the new protocol, and our latest update revealed little improvement.
The first step in migration to IPv6 is to start using a proper dual-stack IPv4/IPv6 connection. In the Netherlands, dual-stacks are available from access providers such as Solcon, XS4ALL and Helden Van Nu. (Helden Van Nu mainly serves the SME market, but consumers can use their services as well.) Nevertheless, the pragmatic reality is that you can't yet host internet services yourself without a static IPv4 address. And, to the best of our knowledge, XS4ALL and Helden van Nu are the only providers who offer static addresses as standard. With Solcon, you get a semi-static IPv4 address, i.e. an address that doesn't usually change, and certainly not without plenty of warning. It's also worth noting that you have to fully configure your IPv6, otherwise you are part of the problem.