IPv6 vs IPv4

IPv6 is the upgraded successor to IPv4, and consist of hexadecimal values instead of integers. An IPv6 looks something like 2a01:4f9:3081:399c::1, while an IPv4 looks like 1.1.1.1. IPv6 using 128-bit alphanumerical values compared to IPV4's 32-bit numbers means that there are way more possible IPv6 addresses (340 undecillion compared to 4.3 billion), this means that they are also way cheaper.

While an IPv4 from Hetzner is ~2$/month, most servers come with a free /64 IPv6 block, which is over 18 quintillion IPs. This means we can give everyone a free public IPv6, while it would be too expensive to give everyone an IPv4. If you need to expose a web service you can use the reverse proxy, but if you need to directly access a port you cannot do that over IPv4, and you have to use IPv6.

You can view your public IPv6 on the dashboard.

IPv6 Support

Currently, IPv6 support worldwide sits at around 45%, to test if you can use IPv6 you can use https://test-ipv6.com/.

Binding to IPv6

To bind to IPv6, you need to use :: instead of 0.0.0.0, :: will bind to all interfaces, including IPv4. You can then access your service with [ipv6]:port for example [2a01:4f9:3081:399c::1]:8080. And if you want to point a domain at your ipv6 you can do so with a AAAA record.