How to Know if Someone is Network-Connected to Your PC
How do you find out who else on the network is using your PC? Which other computers on the local network are peeking into your folders? You may not know, but your computer does. Want to know the answer? Follow these steps:
From the Start menu, choose All Programs→Accessories→Command Prompt.
The Command Prompt window opens.
Type netstat and press the Enter key.
The netstat command displays network statistics. In its basic form (what you typed), current local connections to your computer are displayed. You see something like this if another computer is using one of your PC’s shared folders:
Active Connections Proto Local Address Foreign Address State TCP 192.168.0.103:139 192.168.0.101:60172 ESTABLISHED TCP [fe80::e1fe:4a18:c135:883f%8]:445 MonsterX:50209 ESTABLISHED
The output is, admittedly, technical. (You should expect no less from the command prompt.) What you’re looking for is the other computer’s network name, such as MonsterX, as shown in the code example.
Type exit and press Enter to close the Command Prompt window.
If you cannot determine another computer’s name from the netstat command output, pay attention to the IP addresses. You have to cross-check the IP address displayed with that of other computers on the network, which can be a pain. But that’s the only other way to use the command.
The output also doesn’t explain exactly which folder the other computer is using. In fact, the other computer may not even be using a folder. It could be using a printer or accessing something else. The mystery of it all!
The netstat command can also be used to determine which Internet connections are active on your computer. Type netstat -a to see the list, which can be quite extensive.