I have a Linksys WRT54G. I run a half-life server behind it, have for years. From within the local network, computers that connect to the router via cat5 can connect to this half-life server. Computers that connect via wireless connection can not, but get a Steam error. It is becoming obvious to me that there is something fundamentally different between the wired connections and the wireless connections, but what? There is no firewall, what else would be different?