Port forwarding for a Core Keeper server
Core Keeper breaks the pattern: most players never forward anything at all. You normally join through a Game ID, and the game's own service sets up the connection.
Your setup
Choose the firmware family rather than your exact model — every router in a family shares the same menus.
Out of the box it is 27015. If you changed that, use whatever you set in the port setting in the server config.
The local address of the computer that runs the server. Find it with ipconfig on Windows or ip addr on Linux; it will begin with 192.168, 10. or 172.
Open these
Your firmware takes ranges, so each line here is one 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
Good news: this game has no remote-admin port that could be exposed by mistake. Forward the ports on the left and stop there.
Step by step: your router
- 1
Give the server a fixed local IP
A forwarding rule targets a single local address. If the server comes back from a reboot with a new one, the rule quietly points at an empty address — which is how forwards seem to "break by themselves".
On this router:look for DHCP Reservation, Address Reservation, Static Lease or Manually Assigned IP
- 2
Open the router admin page
From a device on the same network, open one of these in a browser:
- 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 Use the same number for the external and internal port. You can make the external one different, but then every player has to connect on that new number, so keep them identical unless you have a specific reason not to.
- 5
Let the server through its own firewall
The router is now sending traffic to the right computer, but that computer can still turn it away. Windows Defender Firewall is the usual offender: it blocks a newly installed dedicated server by default, and from outside that is indistinguishable from a broken forward.
Take it with you
Core Keeper — port forwarding rules ----------------------------------- 27015 UDP -> <server local IP>
Check whether it worked
Always test from outside your network. A connection from another device in the house proves nothing: that traffic stays on your LAN and never passes through the rule you just created.
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The usual mistake
If a Game ID is what is failing, a forwarded port probably will not help — the two routes are independent, and the dedicated server's direct port only comes into play when you connect by address. Work out which of the two you are really using before you touch the firewall.
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Skipping port forwarding
A dedicated server keeps the world alive between play sessions. The relay solves reaching the server; hosting solves the server being there at all, and those are separate problems.