Open TCP port in Windows 7 and read incoming data, what program to use?

Question

I have an external device which can connect over GPRS to the Internet using a SIM card and I want to see what data it sends. I can program it to use my computer as a server and then use a program to read what it sends. The problem is that I don't know what program to use to read the incoming data. Any ideas?

Device on the Internet > My home router > Port forwarding > My computer I tried Windows 7 Telnet Server but I can't read what is coming.

Answer 1

I think Wireshark is the most common tool for inspecting network traffic. It would also allow filtering data from a specific port.

Answer 2

If you know that it connects to a particular port (or you can tell it to), netcat might be the simplest way to capture the data going to that port, and none other.

nc -l -pport_number  >output_file_name

The -l option puts netcat into listen (i.e., server) mode; without it; netcat acts much like telnet client.

Resources:

• NetCat Tutorial
• Wikipedia entry

Note: On some versions of netcat, -l implies -p, so you should say just -l and then the port number.

Answer 3

You could try TCPView (a free utility from Microsoft from their takeover of Sysinternals). It's a GUI-based interface so you should get up and running relatively quickly.