CraftyEyeballs
by NoahvdAa
CraftyEyeballs changes how the Minecraft client chooses between IPv4 and IPv6 addresses when it connects to a server, so that IPv6 can be preferred.
What it does
Normally a service reachable over both IPv4 and IPv6 is treated as a dual-stack host: the client tries both addresses and keeps whichever one responds first. Minecraft's client does not do this. It tries only the first address it finds, which is usually IPv4, so a server reachable over both protocols is still always reached over IPv4, even when IPv6 is the only one available.
CraftyEyeballs replaces that behavior with the Happy Eyeballs algorithm. The client attempts both IPv4 and IPv6 addresses and uses the first one that answers, with IPv6 preferred when both work. This lets a server move to IPv6 gradually while keeping IPv4 clients, and lets an IPv6-only player connect without a separate hostname. The mod is client-side only, so servers need nothing installed. It runs on Fabric and is published for 1.20.4, with a single file, version 1.0.0, released on 2024-02-06.
The mod is open source under the GNU General Public License v3.0 only. Its source code and issue tracker are public, and the client needs it only when players want the IPv6 preference.
Key features
Happy Eyeballs connections
The client tries IPv4 and IPv6 addresses together and uses whichever responds first, following the Happy Eyeballs algorithm.
IPv6 preference
When both protocols work, the client prefers IPv6, so servers that support it are reached over that protocol.
IPv6-only server access
Players can reach a server that is only available over IPv6 without needing an IPv4 fallback address.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Who it’s for: Players whose networks or servers use IPv6, and server owners planning to move to IPv6 without cutting off IPv4 clients.
Questions
Does CraftyEyeballs need to be installed on the server?
Which loader does CraftyEyeballs require?
Does CraftyEyeballs stop clients from connecting over IPv4?
In the catalog
CraftyEyeballs is one of 36,990 Utility mods on ModsFinder, and one of 25,772 Utility mods for Fabric. 13,907 mods support Minecraft 1.20.4.
More from NoahvdAa
Similar mods
What the author says
It's been more than ten years since the world has run out of IPv4 addresses and internet providers are finally starting to offer full IPv6. While the transition is progressing painfully slowly, progress is being made and more and more services are reachable over just IPv6 every day. Minecraft servers, however, are…
Official listing
- Modrinth page
- modrinth.com/mod/craftyeyeballs
- Owner
- NoahvdAa
- Published
- 2024-02-06
- Updated on Modrinth
- 2024-02-06
- Facts verified
- 2026-10-15