AssaultCube Server Not Showing in the Server List? How to Fix It

An AssaultCube 1.3 server only appears in the public server browser when it registers with the master server, and that needs four things: a valid server auth key passed with -Y, UDP ports 28763 and 28764 reachable from the internet, a player limit of 16 or less, and a map rotation with at least two different maps. Miss any one and the server quietly runs as LAN only. The server console tells you which case you are in, so start there.

Read the server output first

When the server starts, watch the first lines it prints. A working server shows:

looking up ms.cubers.net:28760...
master server registration succeeded

If the success line is missing, the server is running as LAN only. Work through the causes below in order. The first two are settings, the rest are network and list rules.

Cause 1: No auth key, or a broken one

Since version 1.3, every public server needs an identity key. In the official docs' words, without a key the server is LAN only. This is by far the most common reason a new server is invisible, because older guides written for 1.2 never mention it.

To make a key:

1. Open the AssaultCube client (not the server).
2. Press / and type authkey new server.
3. Open config/authkeys.cfg in your client folder.
4. Copy the private key from the line that starts with // priv or authkey add.
5. Pass it to the server: -Y followed directly by the key, in config/servercmdline.txt or on the command line.

Check the key carefully. It must be exactly 64 characters, using only 0 to 9 and a to f. A stray space, a missing character or the public key instead of the private one will fail. Keep this key private: it is your server's identity on the list, and anyone holding it can claim to be you.

Cause 2: The master server is switched off

Look for an -m switch in your command line. -mlocalhost is the documented way to hide a server, and it is easy to copy from someone's private setup without noticing. Remove it, or set it back to the default -mms.cubers.net. On a hosted server, check the Master Server field reads ms.cubers.net.

Cause 3: The ports are not open

The docs are blunt: the most common reason for a registration failure is incorrectly forwarded ports. AssaultCube uses two UDP ports:

If you moved the game port with -f, the info port is always that number plus one, so -f30000 means you must forward 30000 and 30001. Forward both as UDP, not TCP, to the local IP of the PC running the server, and allow them through the firewall. On Windows, Defender often blocks the server executable the first time it runs, so check the inbound rules too.

A quick way to tell which half is broken: if friends can join with /connect your.ip 28763 but the browser never shows the server, the game port is fine and the info port is the problem.

Also watch for carrier grade NAT. Some internet providers, especially on mobile and fixed wireless plans, share one public IP between many homes. If the WAN address on your router does not match what a "what is my IP" site shows, no amount of port forwarding will work. Our guide to hosting without port forwarding explains the options.

Cause 4: Too many player slots

The documentation states that 16 is the maximum player count that still registers with the master server. A server started with -c20 or -c32 runs fine for direct connects but will not be listed. Drop it to -c16 or lower.

Cause 5: Your rotation breaks the list rules

The master server has a few house rules for what counts as a real public server. The documented one: servers whose rotation has fewer than two different maps, or fewer than three if they all run the same mode, may be removed from the list. A maprot.cfg with a single ac_desert line is the classic way to trip it. Add a few maps. Our map rotation guide shows the line format and mode numbers.

Servers that change core gameplay can also be taken off the list by the AssaultCube team. A normal rotation of stock modes is never a problem.

Cause 6: Version mismatch

A 1.3 server is listed for 1.3 clients. If you or your friends still run 1.2, you will not see each other's servers, and older clients cannot join 1.3 at all. Everyone should install the current release from the official download page.

Fix checklist

Skip the networking entirely

Most of these problems come from home networks: routers, firewalls and shared IPs. On a GamezServers AssaultCube server both ports are already open on a fixed address, with DDoS protection in front. The Server Auth Key and Master Server fields sit in the control panel next to max players, description and passwords, so listing your server is a matter of pasting the key and restarting. If it still does not show, the live console prints the same registration lines described above.

FAQ

How do I get an AssaultCube server auth key?

Run the client, press /, type authkey new server, then copy the private key from config/authkeys.cfg. Pass it to the server with -Y.

Can I use the same auth key on two servers?

Each key is the identity of one server on the master list. Generate a separate key for each server you run.

Can players join an unlisted AssaultCube server?

Yes. Unlisted servers still accept direct connects. Players press / and type connect with your address and port separated by a space.

How long does it take to appear in the list?

Registration happens when the server starts. Once the console shows the success line, refresh the server browser in the client.

Does a player password hide the server?

No. A password protected server still registers and shows in the list. It just asks for the password on join.