As a networker, ipv6 is the future. I’m a fan of it, but I don’t really talk about it anymore because there’s no point.

I threw in the towel after an ISP messed up so badly that I just couldn’t bother anymore.

At a previous job a client I was doing some work for got a new internet connection at a new site, the ISP ran brand new fiber for it. This wasn’t a new building or anything, but the fiber was new. They allocated them a static IPv4 thing as usual, and I asked the tech about V6, and they said we would have to take it up with the planning team, so I did. I was involved in the email chain at the end of the sales process to coordinate the hookup. So I asked. After many emails back and forth, I was informed the connection was allocated.

They allocated one single IPv6 subnet directly off of their device. I couldn’t even.

For those that don’t understand, the firewall we had connected to the device is an ipv6 router. What normally happens, especially in DHCP customer connections, is that the router will use DHCP-PD to allocate a subnet for the router to use on the LAN, and automatically set up a route to say “reach this subnet we allocated for this router, via this router” kind of thing. I’m dramatically simplifying, but that’s the gist. In DHCP-PD, the router will also have an IPv6 address on the ISP-facing link to facilitate the connection. In the case of the earlier story, they gave us an entire subnet to communicate between the ISP and the router, and didn’t give us a subnet for the client systems inside the network.

I did ask about this and I can only describe their reply as “visible confusion”.

I know many who will still be confused by this point are people who have not used IPv6; to explain further: the IP on your local (LAN) systems needs to be a public IP address, because the router no longer does network address translation when sending your data to the internet. So the IP on the router has no bearing on your computer having a connection to the internet over v6. If your local computer does not have a globally unique ipv6 address, you cannot use IPv6. There are ways around this, NAT66 exists but it’s incredibly bad practice in most cases. The firewall I was working with didn’t really support NAT66 (at least, at the time) and I wasn’t really going to set that up.

ISPs are the reason I gave up on IPv6.

I’ll add this other story to reinforce it. I’ll keep it brief. A different ISP for a different company at a different site entirely. The client purchased a static IPv4 address, and I asked about IPv6, as you do. To preface, I know this company and used them for my own connection at the time. They have IPv6 for residential clients via DHCP-PD. I was told, no joke, that because of the static IPv4 assignment, and how they execute that for businesses, that they couldn’t add IPv6 to the connection, at all.

The last thing I want to mention is a video I saw, which is aptly named “CGN, a driver for IPv6 adoption” or something similar. It’s a short lecture about the evils of carrier grade NAT, and how IPv6 actually fixes pretty much all the bs that goes with CGN, with fewer requirements and less overhead.

IPv6 is coming. You will prefer IPv4 until you understand how horrific CGN is.

IPv4 dried up a long time ago. But it’s different for every country. Countries like US and UK simply took over large blocks of IPv4 addresses and countries like Brazil got fucked. So, if you’re in a country with a large pool, you won’t notice any issues today, but if you’re not so lucky, a lot of internet services are not accessible to you because some dickhead got IP banned and that IP is shared by thousands if not millions of users in your country.