How to track socket activity on a computer?

Question

I want to write a program from scratch to see socket activity, what they send, what they receive, etc. I do not want to use the library because it is more for academic purposes than anything else.

Where to begin?

Just to be clear: my program will not connect to anything and does not create any socket, it just wants to listen to activity on the computer.

Any thoughts (on any OS) about where to start will be appreciated.

Thanks in advance.

Answer 1

Take a look at libpcap / WinPcap .

Answer 2

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API- UNIX Windows, BSD- Berkeley Sockets, , , , IO .

Linux (tcpdump, ethereal ..), . Windows, MS , - Google Sysinternals TDImon MS.