I want to test going IPv6-only in my home. I already enabled IPv6 functionality on my router. I can get two addresses from it on my computer: 192.168.0.x and 2402:xxxx (sorry, cannot remember the full address). My router shows two WAN IP: 100.64.x.x and 2402:xxxx.
If I disable IPv4 DHCP on my router, my computer shows only the IPv6 address, but many websites break. Is it not possible to go IPv6-only?
Sorry if I am not clear, I am not good in speaking English.
The only practical way to go IPv6 only right now is to use NAT64. This allows you to access IPv4 websites using your computers IPv6 address however it's not trivial to configure, you'll need a proper router(or Linux server), not just whatever router your ISP provides, and said router will still need an IPv4 WAN address but your PC, phone, etc can go IPv6 only and still access legacy sites like GitHub etc. For reference my home network is IPv6 only. I use jool for NAT64
Most likely, yes. (Are there any off-the-shelf home routers which support NAT64 out of the box??)
You need to be familiar with the command lines too, but that's almost a given since it's OpenWrt that we are talking about. Follow the tutorials here for activating NAT64 on an OpenWrt router.
I did mention not trivial also DNS64 isn't that difficult comparatively. Especially since Google public DNS offers it. Setup the NAT, set your nameservers to 2001:4860:4860::6464 and you're good.
Unfortunately until website owners starts being aware that IPv6 exists, you can only go IPv6-only if you have NAT64.
Look at this:
From this screenshot I can see a couple instances (3 Hetzner IPs, one OVH, one DigitalOcean, one AWS and one from AS211772 (they also do have an IPv6 range announced)) that are IPv4-only. All of them could have IPv6 support but they only add the A record on their DNS records and call it a day. It is very annoying to see that.
In general, yes, this is possible. However, it is more difficult than just disabling IPv4 on all your devices.
First of all, there are still many (more or less relevant) sites that still are IPv4-only. If you want to reach them via your IPv6-only home network, you need to set up or use services that translate your traffic from IPv4 to IPv6 and vice versa. But this can be error-prone and needs work and understanding of the matter from your side.
The easiest is that you just leave IPv4 and IPv6 enabled in parallel. Your operating system will usually prefer IPv6 over IPv4 if it's available.