How to port forward a Core Keeper server
Core Keeper is the outlier on this list: most people never need to forward anything. Servers are normally joined through a Game ID, which negotiates the connection through the game's own service.
Your setup
Pick the firmware family, not the exact model — the menus are identical across a range.
Default is 27015. If you changed it, it is the value of the port setting in the server config.
The private address of the machine running the server — ipconfig on Windows, ip addr on Linux. It starts with 192.168, 10. or 172.
Open these
This firmware accepts ranges, so each line below is a single rule.
- 27015 UDP
27015UDPGame trafficCore Keeper servers are normally reached through their Game ID rather than an address, in which case no forwarding is needed at all.
Do not open these
This game has no remote-administration port to get wrong. Forward only what is listed on the left and nothing else.
Step by step: your router
- 1
Give the server a fixed local IP
A forward points at one address. If the server picks up a different one after a reboot, the rule silently starts pointing at nothing — this is why forwards "stop working" on their own.
On this router:look for DHCP Reservation, Address Reservation, Static Lease or Manually Assigned IP
- 2
Open the router admin page
Try these addresses in a browser on the same network:
- 192.168.0.1
- 192.168.1.1
- 192.168.2.1
- 10.0.0.1
Almost always printed on a sticker on the router itself.
- 3
Find the port forwarding page
Port Forwarding, Virtual Server, NAT, Applications & Gaming, or Port Mapping
Vendors use at least six names for the same feature. Whatever it is called, the page you want is the one asking for a port, a protocol and a device on your network. If the external and internal port fields both exist, set them to the same number.
- 4
Create one rule per line
a description field, if there is one External / WAN / Public / Service port Internal / LAN / Private port Protocol Internal IP / Device / Server IP Core Keeper 27015 27015 UDP your server’s local IP External and internal port are the same number here. Changing the external port is possible, but then everyone connects on the new one, so keep them matched unless you have a reason.
- 5
Let the server through its own firewall
The router now sends traffic to the machine, and the machine can still refuse it. Windows Defender Firewall in particular blocks a freshly installed dedicated server by default, which looks exactly like a failed forward.
Take it with you
Core Keeper — port forwarding rules ----------------------------------- 27015 UDP -> <server local IP>
Check whether it worked
Test from outside your own network. Connecting from a machine in the house proves nothing — that traffic never leaves the LAN and never touches the rule you just wrote.
What usually goes wrong
If you are here because a Game ID is not working, forwarding a port is unlikely to be the fix — the two paths are separate, and the dedicated server's direct port only matters if you are connecting by address. Confirm which of the two you are actually using before changing firewall rules.
Not forwarding at all
A dedicated server is what keeps the world running between sessions. The relay handles reachability; hosting handles availability, and they are different problems.