2024-04-15
Having IPv6 for public servers is almost always merely nice, not essential
Today on lobste.rs I saw a story about another 'shame people who don't have IPv6' website. People have made these sites before and they will make them again and as people in the comments note, it will have next to no effect. One of the reasons for that is a variant on how IPv6 has often had low user benefits.
As a practical matter, almost all servers that people want to be generally accessible need to be accessible via IPv4, because there are still a lot of places and people that are IPv4 only (including us, for various reasons). And as the inverse version of this, practically everyone needs to be able to talk to public servers that are IPv4 only, even if this requires 6-to-4 carrier grade NAT somewhere in the network. So people operating generally accessible public servers can almost never go IPv6 only, and since they have to have to be reachable through IPv4 and approximately everyone can talk to them over IPv4, adding IPv6 support has only a moderate benefit. Maybe some people can avoid going through carrier grade NAT; maybe some people will get to feel nicer.
(You can choose to operate a website or a service as IPv6 only, but in that case you're cutting off a potentially significant amount of your general audience. This is not something that many site and service operators are enthusiastic about. Being IPv4 only has much less effects on your audience. This is related to how IPv6 mostly benefits new people on the Internet, not incumbents. Of course IPv6 only can make sense if your target audience is narrower and you happen to know that they all have working IPv6.)
When you have a service feature that is merely nice instead of essential and which potentially involves some significant engineering complexity, is it any surprise that many organizations put it rather far down their priority list? In my view, it's basically what one would expect from both an engineering and business perspective.
(In my view the corollary to this is that general server side IPv6 adoption could be best helped by some combination of making it easier to add IPv6 and making it more useful to have IPv6. Unfortunately a whole raft of historical decisions make it hard to do much about the former, cf.)