Using the Internet without IPv4 connectivity

Slightly misleading title, this is more “getting to the IPv4 internet via an IPv6 tunnel through a VPS”. Also just called 4in6.

Interesting nonetheless!

We find at our ISP that if we break something with IPv4 we experience a very different type of support issue to if we break IPv6. Breaking v4 results in, broadly, a pretty hard “down” state. While folks are unhappy, it is at least simple. Breaking v6 results in weird, and a partial down, which manifests for the users as partial outages, slow starts due to fall back, etc. Especially if their gateways believe there is v6 when there isn’t.

Mirrors my experience. IPv6 issues are frustratingly hard to triage and reproduce, lots of “works on my machine” etc.

There's certainly a long tail of IPv4, but the last time IPv4 broke at home, my wife didn't even notice since Google, Facebook, Apple/iCloud, and most CloudFlare-hosted properties all still worked over IPv6.

When my IPv4 died last time, I noticed it mostly because Github didn't work anymore. These days, most consumer websites just work on IPv6. That said, people whose routers were only provisioned IPv4 DNS servers did have a full outage.

If Microsoft would get off their incompetent assets already, my biggest concern would've been remembering the mDNS hostname I've assigned to my router so I could log in and see if IPv4 is back already.

I think it's because of all of those transition mechanisms and fallback code added over the years. IPv6 fails the same way IPv4 does, but because of the terrible bullshit ISPs do to IPv6 connections, you end up with tons of software triggering obscure timeouts and fallback mechanisms that lead to a system of almost working networking code.

If the absence of IPv6 would've been treated the same way absence of IPv4 is, troubleshooting would've become a lot clearer. In fact, it probably would've been easier because ISPs can't just ignore and disable ICMP on IPv6 so you can actually get a hunch where in the network the problem is rather than seeing traffic vanish into the void.

The POSIX bug tracker is not accessible over IPv6, either, because their AWS setup does not support it. The website administrators refused to fix this[1].

[1] https://austingroupbugs.net/view.php?id=1623

Most ISPs still just block IPv6 altogether because most small businesses seem to try IPv6 once and then forget to eg update their AAAA records so to the user it looks like their favorite niche thing works when they're on <low quality ISP at friend's house/coffee shop> but not on the one they're paying for which creates problems.

It's kind of a weird issue, I don't know if there are nice solutions other than hoping IPv4 just goes away eventually. Happy eyeballs was supposed to solve this but often the problems manifest way up in the application layer and there's no general protocol for solving that without some kind of very leaky abstraction because the application can do anything.

The compromise I personally have to make things smooth is enabling ipv6 in the network and then disabling ipv6 DNS on all of my browsers which is pretty unsatisfying.

[citation needed]

> Most ISPs still just block IPv6 altogether

That’s increasingly not true, at least in developed countries. Traffic to Google in the US has been majority IPv6 since a few months ago.

The Meta Quest software also sucks at this. You’d expect an essentially new platform struggling with this. Valve is basically all IPv4 afaict too.

Pretty annoying and lazy if you ask me.

Majority mobile and majority ipv6 are basically the same thing.

My ISP (TekSavvy) manages to semi regularly screw up ipv4 and what I notice is that "big" sites like Amazon, Google, Facebook, SO, etc all work as before, but it's the in-between sites, someone's blog on a search result, etc— that's the stuff that breaks.

GitHub is definitely a part of that long tail.

It's easy enough to port forward v6 on some server to v4 GitHub - i'm doing it right now but can't remember the address. Think there's any demand for this, considering you can save $0.50-$2 per month per server by not having v4?

And developing countries don't have much choice since they have to share about 5 addresses per city.

I mean, basically every major mobile in the developed world adopted IPv6 when they were rolling out new core infrastructure to handle LTE (T-Mobile USA being notable as one of the first to go IPv6 only). When you consider the deployment of VoLTE (and now VoNR for 5G networks) in particular, rolling out IPv6 internally removes a lot of nastiness that SIP/IMS have with NAT (and CG-NAT in particular), so it's little surprise that it happened.

What surprises me more is the very mixed state of small to midsized ISPs. Sparklight (regional cable provider) still does not support IPv6 in any fashion even though it would be financially beneficial to auction off a significant portion of its v4 holdings (nearly 1.3mm addresses), deploy DNS64+NAT64 (plus CG-NAT as a fallback) and hold onto a chunk for their business customers who still need inbound v4 connectivity. My local fixed-wireless ISP that's my only real option (love them, but this is a bugbear of mine) since I moved last year only offers CG-NAT, and I know their equipment can handle v6 fine which would save them some resources (no expensive state tracking on edge equipment or dedicated CG-NAT gateways) and provide a better customer experience (multiplayer games, VoIP traffic, etc.)

Astound still doesn’t either and they are large.

Your information is either outdated or very specific to your locale.

Not only do ISPs here support IPv6 by default these days but they have even started only giving IPv4 connectivity via carrier grade NAT for new customers - you can still ask for a real IPv4 address for now but it's not there by default and the ISP reserves the right to take it away.

The Valve stuff is extra infuriating because a lot of their assets seem to be hosted on CDNs that do have IPv6, but their backend servers are stick with IPv4. When IPv4 breaks, you can look and buy games, but actually playing them will fail because of DRM checks.

Some VPS providers already provide free IPv4 solutions.

Setting up a server works fine for server stuff, but it'd get you blocked and banned everywhere for having a data center IP while just browsing or trying to watch Netflix.

For my servers I could do it the other way around and save a dollar per month, but then I'd be sending emails from a residential IPv4 address, which will never ever make it past any spam filter.

My mobile carrier here in the Netherlands doesn't do IPv6. Mobile traffic doesn't automatically mean IPv6, unfortunately.

I have my VPN permanently enabled for Pihole reasons anyway, so my IPv6 access works that way, but it's pretty stupid.

It's not just mobile. My previous (Verizon Fios in NYC) and current (Cox in Tucson) home ISPs both support IPv6.