Evt musst du noch die Ports für Steam freigeben:
Steam Client
* UDP 27000 to 27015 inclusive (Game client traffic)
* UDP 27015 to 27030 inclusive (Typically Matchmaking and HLTV)
* TCP 27014 to 27050 inclusive (Steam downloads)
Dedicated or Listen Servers
* TCP 27015 (SRCDS Rcon port)
