Multiplayer Connectivity Help

Online games

KeeperFX uses UDP port 5556 by default, it automatically tries UDP hole punching, NAT-PMP, UPnP, and direct connections over IPv4 and IPv6.

Joining a lobby is much easier than hosting a lobby. So if you're having issues:

1. Try switching who is hosting.
2. Try joining a known-working host player from the discord.
3. Open the host's router settings and manually port-forward UDP 5556 in the IPv4 section. Alternatively, enable NAT-PMP or UPnP in the host's router.
4. Be sure to use the same KeeperFX version on every computer.
5. Visit test-ipv6.com to check whether the host has working IPv6 internet access, IPv6 sometimes just needs to be enabled in the router settings.
6. IPv6 may allow hosting without IPv4 port forwarding, but both the router firewall and PC firewall must have exceptions for KeeperFX.
7. Restart KeeperFX after changing network settings.

KeeperFX uses a matchmaking master server to introduce players, then attempts a direct UDP connection over IPv4 or IPv6. This online lobby discovery requires a connection to matchmaking.keeperfx.workers.dev and stun.l.google.com, which some countries may have trouble with. Firewalls, DNS filters, routers, and restricted networks can block these services or block UDP hole punching.

If the host has CGNAT or double NAT, port forwarding may not work. With double NAT, forward the port through every router. With CGNAT, ask the ISP for a public IPv4 address or use IPv6.

Some networks simply cannot establish peer-to-peer UDP connections.

To use Direct Connect over the internet, open the launcher menu beside Play, select Direct Connect, enter the host's public IP address or hostname, and click Play. Add the port to the address if the host is not using the default, such as example.com:6000. The host may need to forward the selected UDP port in their router.

LAN games

Use the LAN Lobby when everyone is on the same network and running the same KeeperFX version. UDP 5557 handles lobby discovery, while a separate UDP port (5556 by default) handles the game.

If the lobby does not appear, open Direct Connect from the launcher menu beside Play and enter the host's local IPv4 address, such as 192.168.1.50. If Direct Connect works, check whether UDP 5557 is blocked. If it fails, allow KeeperFX through both firewalls, temporarily disable VPNs, and disable guest-network, AP-isolation, or client-isolation settings. Restart KeeperFX after changing network settings.

LAN games need no internet port forwarding. Do not use the router's public IP address.