Check if your Core Keeper server is online
Core Keeper can be joined by game ID or queried directly on its port, which is why 'friends can join but the checker says offline' comes up so often with it.
The ports Core Keeper uses
Joining by game ID runs through the publisher's relay and has nothing to do with your ports. This check uses a direct query on your server's UDP port, so it is testing a different path from the one your friends use. A server joined through the relay can be completely unreachable directly and still work fine for them.
Every port a default Core Keeper install uses
With the game port left at 27015. If you changed it with the port setting in the server config, the other ports move with it.
| Port | What it is for |
|---|---|
| 27015 UDP | Game trafficRequired Core Keeper servers are normally reached through their Game ID rather than an address, in which case no forwarding is needed at all. |
Still offline? Try this
Joining by game ID working fine means a failure on this page is normal, not something to fix. Forward the UDP port only if you want direct connections and a public listing on top.
What a Core Keeper server needs to run well
- Memory, 4 players
- 3 GB
- CPU cores
- 2+
- Disk
- 5 GB+
Light, with cost growing slowly as the world is explored.