Server connection issues

When the panel shows a game server as offline — or as online but with an empty player list — it can’t reach the server’s query (UDP) or RCON (TCP) port. This page walks through the checks in order, from “is the server actually online?” to “test it with the diagnostic tool.”

If you haven’t yet, Network ports lists what needs to be open and from which direction.

Quick checklist

Before reaching for the diagnostic tool, confirm the basics:

• Your firewall isn’t blocking the game server’s port on UDP or TCP, from the panel host’s perspective.
• The game server is online to people outside your network. You can join it in-game from off-network.
• You can use RCON from in-game (e.g. rcon_password yourpass; rcon status in the developer console). If this fails too, see TCP errors below.

If all three pass and the panel still can’t read the server, run the diagnostic tool.

The diagnostic tool

A small sb_debug_connection.php ships in the panel’s web root. It tests the UDP query and RCON sides independently and reports exactly what fails.

Configure

Open sb_debug_connection.php in your editor and fill in the server details near the top:

$serverip = "";    // e.g. "1.2.3.4"
$serverport = "";  // defaults to 27015 if left empty
$serverrcon = "";  // optional; leave empty to only test serverinfo

Run

Navigate to the file in your browser:

https://example.com/sb_debug_connection.php

If everything’s wired right, it’ll print the server’s info (map, hostname, player count), the result of the RCON handshake (if you filled in a password), and the player list.

If something fails, it’ll tell you which step — that maps directly to the sections below.

Caution

The diagnostic tool exposes server info and (if you filled it in) the RCON password. Delete sb_debug_connection.php when you’re done — don’t leave it on a production install.

UDP errors

The panel can’t read server info / player list back from the game server.

UDP is the protocol Source uses for its A2S queries — the panel sends a small “tell me about yourself” packet and waits for the reply.

Common causes:

• A firewall is blocking UDP, either on the panel host (outgoing UDP to the game server’s port) or on the game server host (incoming UDP from the panel’s IP). Open it in both directions.

• The game server is behind NAT without a UDP port-forward. Add one for the game server’s port on UDP.

• The game server has listip-banned the panel’s IP. Source game servers maintain a separate IP block list (cfg/banned_ip.cfg) that silently drops packets from blocked IPs. If you see the panel’s IP in there, remove the line and run removeip <IP> via RCON.

• The game server isn’t bound to a public IP. If srcds is started without -ip, it can default to a private interface. See Bind-IP fix below.

TCP errors

The panel can read server info but can’t open an RCON session.

RCON uses TCP. The panel reads server info via UDP (which works) but the TCP handshake to push admin commands fails.

Common causes:

• A firewall is blocking TCP on the game server’s port from the panel’s host. UDP and TCP are usually allowed together, but some restrictive firewalls treat them separately.

• The RCON password is wrong in the panel. Edit the server under Admin Panel → Server Settings, fix the password, save.

• The game server isn’t listening for RCON at all. If you can’t RCON from in-game either, the server needs -usercon in its launch parameters to enable RCON for in-game use too.

• The game server isn’t bound to a public IP. See Bind-IP fix below.

Bind-IP fix

If your dedicated server has multiple IPs, or runs on a host with both public and private interfaces, srcds can default to listening only on the loopback or private interface. The panel can’t reach a loopback-bound server from another host.

The fix is to explicitly bind to the public IP via the -ip launch parameter:

./srcds_run -game tf -ip 1.2.3.4 +port 27015 ...

Restart the server, then re-test from the panel.

Empty player list specifically

If the panel shows the server as online with the right map and hostname but the player list is empty even when you can see players in-game, the server’s hiding the player list from external queries. The fix is one line in server.cfg:

host_players_show 2

Reload the map (or restart the server) and the panel will see the full player list on its next poll.

Still stuck?

Post in #help-support with:

• The output of sb_debug_connection.php.
• Whether you can RCON from in-game.
• Where the panel and the game server are hosted (same machine, same network, different providers, …).
• The game server’s launch parameters and server.cfg (redacting the RCON password).

We’ll narrow it down from there.