Hopefully this saves people some time and energy.
I have a Cisco / Linksys E2000 Wifi Access point. My son has an inexpensive PC connected directly to one of the ports on the back. We were trying to get a LAN game going. The game is called “Day of Defeat : Source, a Half-Life mod like Counter Strike. I’ll another post on that story later.
For some reason, we couldn’t get my Mac (on Wifi) to see the LAN game server he was running. The Steam app has a tab called “LAN Servers” and it kept reporting “There are no servers running on your local network.” I did a lot of searches on the internet and came up with nothing.
Finally, I had to put my tech hat on and start troubleshooting the IP layer between the machines. This took some time, but the solution was not obvious, and not too surprising given how these access points are developed.
I had to put the “Wireless > Basic Wireless Settings > Wireless Mode” into “Wireless-G Only”. This defeats the purpose of having an N router, but whatever.
As soon as I made that change, everything started working. The networks became connected. All of the IP diagnostics passed and the game server that he created showed up on my ‘LAN’ tab in steam.
There is no reason I can think of that this should have occurred other than there is some bug in the access point software.