Many people are ok with leaving their network open for others to use. But you might be curious to find out how often others are on your network and using your internet connection. Network Magic will show you this for free thru our Network Map and Intruder Alert features. Just download and install it. You will need to leave that PC on so it can monitor your network.

Make sure “Intruder Alert” is turned on in Network Magic
In the "Tools" menu under options you can find this dialog box.

Intruder Alert does three things for you .

1. Automatically Marks Intruders.
It marks every new device that comes on your network as an intruder on the Network Map. Even if they come on your network while your away, Network Magic will show you the device and details it has learned about that device. It will even show you the MAC address, which is the unique identifier of that devices network card. You can use the device MAC Address and your router’s MAC Address Filter feature to block that device.

2. Tracks Intruders Time on Your Network
It tracks the intruder in the “What’s New” Tab. It will show in read the times that each intruder has come on and off the network

3. Prevents Intruder from Using Network Magic for auto Folder or Printer Sharing.
If the Intruder is using Network Magic and it is marked as an “intruder” then Network Magic will not enable the intruder to participate in Network Magic Shared Folders or Printer Sharing. However, it doesn’t prevent an intruder from using other means to see the folders you have shared out or accessing your printer. I recommend not sharing folders on your network if you are leaving it open for others to join.

What about security on an open wireless network?
I also strongly suggest you make sure you have your software firewall turned on because you will be exposing your PCs to risk when others connect to your network. Network Magic will alert you if your software firewall is not enabled. You will have to configure you software firewall manually if you wish to block an intruder from your shared folders. Having said all this I would recommend that you turn on Intruder Protection in Network Magic even if you want to let your neighbor or friends on. You can just treat them as part of your network and still block unwanted guest.