How do you check a CS2 server?

Counter-Strike 2 servers run on Valve's Source 2 engine and answer the same UDP queries as every Source server: A2S_INFO for the server's name, map and player count, and A2S_PLAYER for the list of connected players. Server browsers and launchers use these queries to show a server before you join it, and you can use them to see whether your own server is up and visible from the internet.

Tool description

Enter the Server Address (an IP address or hostname) and the Port, then press Check Server. You get:

  • The Server Name, Current Map and Game
  • Players out of the maximum, and Bots
  • The Version of the game the server runs, handy after a CS2 update when players can't join an outdated server
  • The Operating System, and whether the server is Password Protected and VAC Secured
  • The Player List with each player's name, score and time on the server

The check runs on our server, which sends the queries over IPv4 to the address you entered. CS2 servers answer them on their game port, 27015 by default.

AI assistants connected to the Rapid Tool Set MCP server can run the same check as cs2_server_checker.

Tips

  • If the check fails, the server may be offline, a firewall may block UDP traffic to it, or it may listen on another port. Hosting panels show the port next to the IP address, as in 203.0.113.10:27016.
  • A server reached through a Steam Datagram Relay address (as in official matchmaking) can't be queried directly.
  • Other Source engine servers, such as CS:GO, Team Fortress 2, Garry's Mod and Rust, answer the same queries; for Counter-Strike 1.6 use the CS 1.6 Server Checker.