Salut.
Il se peut que tu doives ouvrir des ports au niveau de ton par-feu :
The following ports must be open in your firewall and router for Steam and Steam Games to work:
UDP 1200 (used for friends service)
UDP 27000 to 27015 inclusive
TCP 27020 to 27050 inclusive
Computers running Dedicated Servers need these ports open:
UDP: 27015 and 27020 (default HLDS, SRCDS and HLTV port)
TCP: 27015 (SRCDS Rcon port)
If your server uses a different hostport then you will need to adjust the above accordingly.
For help on port forwarding for your Router, please consult this excellent website:
http://www.portforward.com.
For assistance with your Firewall you will need to go to the support site for your particular Firewall. Windows XP SP1 firewall does not require any specific configuration changes for Steam to work
