This might be old news to most, but I just discoverd it so I thought I would share for those that do not know.
So I was tired of leaving my PC on all evening just because I might want to stream some video sometime tonight... My PC is far away from the living room and I dont like to have to go in the back room to fire up the PC and wait for it to boot up if I want to stream some DivX. ( I am lazy) I decided to try to implement "wake on lan" (WOL- that is a PC power setting that will allow your PC to come out of sleep mode due to ethernet activity).
Sounds great right? Not really- your wireless modem/router/whatever probably polls your PC every few minutes to verify network status. So, every few minutes (or seconds) your PC wakes up. Pretty shitty... So brilliant MS decided to add an option to the WOL ability: "only allow management stations to wake the computer". What does that mean? That random LAN traffic will not wake your PC. Only "magic packets" will. What are "magic packets"? Specific lan data that can be sent from various devices and other PC's if you set it up correctly.
The good part: If the 360 is set up as a WMC extender, when you launch WMC from the 360 a magic packet gets sent and the sleeping PC wakes if it is set up to WOL! The PC will not wake from simply browsing the videos folder in the 360 dash, but it will wake from a WMC connect attempt.
No more leaving my power hog PC on for several hours every evening just in case I decide to stream videos! No more complaining from the wife or kids when 360 wont stream video because the PC is turned off!