Ok this ones a guess, I'll test on my dev box shortly, but in the meantime:
A good place to start is in the /proc "virtual" file system. You understand what /proc is about?
Ok /proc is a virtual file system of all the running process of your server, it is dynamically built as the system runs up, you (as root) can modify the files within /proc but any mods will be lost on re-boot.
But getting back to your question try: more /proc/net/* and see what's recorded there?
Good Luck
Laurie.