CS2D Server Not Showing in the Server List: How to Fix It

A CS2D server that runs but does not appear under Find Servers is almost always failing to talk to the U.S.G.N. master server. Check four things: sv_lan must be 0, the first line of sys/usgn.dat must point at the current master server (217.154.200.83|usgn.de since August 2025), UDP port 36963 must be reachable, and you can force a listing with usgn_addserver. While you sort it out, players can still connect by IP.

How CS2D's server list works

CS2D does not use Steam's server browser for its list. Servers register with the U.S.G.N. (Unreal Software Gaming Network) master server, and the game's Find Servers screen asks that master server for the list. If your server cannot reach U.S.G.N., or U.S.G.N. cannot reach it back over UDP, it simply never shows up. Nothing on the server looks broken, which is why this one is confusing.

The same connection also handles U.S.G.N. account logins, so a broken master server link usually shows up in two ways at once: no list entry, and players' U.S.G.N. IDs not being recognised.

Fix 1: Make sure sv_lan is 0

sv_lan 1 is LAN mode. The official help is clear: with it on, the server is never added to the U.S.G.N. list, and internet players cannot see it.

Open sys/server.cfg and check:

sv_lan 0

If you set the server up from the game's New Game screen and copied the sys folder over, LAN mode may have been switched on there. Restart after changing it.

Fix 2: Update usgn.dat (the August 2025 change)

This is the fix most guides miss. In August 2025 Unreal Software moved the U.S.G.N. master server to a new IP. Game clients update themselves, but game servers do not. A server still pointing at the old address drops off the list and U.S.G.N. logins stop working on it.

1. Stop the server.
2. Open sys/usgn.dat (relative to the cs2d_dedicated program).
3. Change the first line to:

217.154.200.83|usgn.de

4. Save and start the server again.

Servers installed fresh from a current download should already have the new line, but any server copied from an older install, or restored from an old backup, may still carry the old one. It takes ten seconds to check.

Fix 3: Check the UDP port

CS2D uses UDP only, on 36963 by default (sv_hostport). The master server needs to reach your server on that port to list it.

• Home server: forward UDP 36963 in your router to the PC running the server and allow it through the firewall. A TCP only rule does nothing for CS2D.
• VPS or root server: open the UDP port in the provider's control panel firewall as well as on the machine.
• Two servers on one machine: give each its own sv_hostport. If both try 36963, one fails or picks a random port, and the list entry points to the wrong place.
• Changed the port? A port change only takes effect after a map change, so run map or restart.

Also check that you are not launching with -port on the command line while editing sv_hostport. The command line wins and the config line is ignored.

The built in mp_natholepunching helps some servers behind home routers, but do not rely on it. Our port forwarding guide covers the router side, including how to spot carrier grade NAT, where forwarding cannot work at all.

Fix 4: Force a listing and read the details

Two console commands help here, typed into the server console (or sent over RCon):

Run usgn_info first. If it shows no connection to the master server, go back to fixes 2 and 3. If the connection looks fine, run usgn_addserver and refresh Find Servers in the game after a minute.

Fix 5: Rule out the client side

Sometimes the server is listed and the player is the problem:

• Their list filters hide password protected, full or empty servers.
• Their game is outdated and still asks the old master server. Updating the game fixes it.
• They are looking for the server name before the server finished starting. Wait for ----- Server started ----- in the console.

Ask one friend to connect by IP. If that works, the server itself is fine and only the listing is wrong.

Joining by IP while you fix it

Nobody has to wait for the list:

1. Open Find Servers in CS2D.
2. Use the option to connect by IP.
3. Enter the server's address and port, for example 203.0.113.10:36963.

For a private group, this is often all you need. A password with sv_password keeps strangers out even when the server is listed. See setting a password on a game server for the general idea.

Quick checklist

The hosted route

On a hosted CS2D server the port is already open and the address is public, so fix 3 is done for you. You still have the file manager and SFTP for sys/server.cfg and sys/usgn.dat, and a live console where usgn_addserver and usgn_info work as normal. Server name and password are in the panel. If you are setting up from scratch, our CS2D server setup guide covers the whole process, and the CS2D page shows plans from 1 GB, which is all this game needs.

FAQ

Why did my CS2D server disappear from the list after years of working?

Most likely the August 2025 U.S.G.N. move. Change the first line of sys/usgn.dat to 217.154.200.83|usgn.de and restart.

How long does a new CS2D server take to show up?

Usually within a minute or two of ----- Server started -----. If it takes longer, run usgn_addserver in the console.

Can players join if the server is not listed?

Yes. They can connect by IP from Find Servers with your address and port.

Does sv_lan 1 hide my server?

Yes. LAN mode keeps the server off the U.S.G.N. list entirely. Set it to 0 for online play.