lib/SteamCondenser/Servers/Sockets/GoldSrcSocket.php
public function rconGetChallenge() {
        $this->rconSend('challenge rcon');
        $response = trim($this->getReply()->getResponse());

        if($response == 'You have been banned from this server.') {
            throw new RCONBanException();
        }

        $this->rconChallenge = floatval(substr($response, 14));
    }
public function rconGetChallenge() {
        $this->rconSend('challenge rcon');
        $response = trim($this->getReply()->getResponse());

        if($response == 'You have been banned from this server.') {
            throw new RCONBanException();
        }

        $this->rconChallenge = floatval(substr($response, 14));
    }
Requests a challenge number from the server to be used for further
requests

@throws RCONBanException if the IP of the local machine has been banned
on the game server
@see rconSend()