I am on a wireless network. Someone has connected to the SSID (which is hidden) and has then broadcast it on channel 11. As a result, anyone can now see our wireless network and can access it through his notebook when he is online. The MAC address is shown in the Wireless utility. How can I track the user down? Finding his IP address would be a good start. Does anyone know how to look up an IP address by MAC Address?

I think you may be confused. A wireless station accessing your wireless router can't broadcast your SSID nor can this wireless station make your network available to everyone else. This is strickly controlled via your wireless router. It would appear you don't have it configured properly. Finding the ip is pointless. Reason is your router provided the ip address via dhcp. Here is what I recommend; 1. Set a new admin password on the router using numbers and letters. 2. Narrow your dhcp scope to only the amount of pcs you have. So lets say you have three pcs your dhcp scope would be 192.168.x.2-4 which is percisely three ips. 3. set a wep/wpa key for your wireless 4. set wireless access via mac address so only the machines you want on can get on. 5. note the mac address of the rouge connection. Depending on your router you should be able to set this mac as blocked. Review your routers documentation for this feature. Give a person a fish, they eat for a day. Suggest they internet search and they learn a skill for a lifetime.

You can not. You might be able to find a transmitter by other methods. With very high tech devices you could even track the receiver. Yes, receivers can be tracked by if. Get backtrack cd to help secure your system. Blank ssid is of no use as you can see. Change keys often and use wanderer's suggestions.

Hey Everyone, Sorry about the mixup. The only real problem is that someone on the network is broadcasting our SSID ... so anyone who happens to see it can easily guess the name of the correct one. Can't see us getting any gadgets to find it (not on our budget in a million years) Any other ideas of tracking him down, I am game.