chances are you're one some strange cutting edge...you may be the first to try what you want to try, and nobody else knows any more than you do, but in that case, would'nt it be cool to be the first to pull it off?
Sorry, I love messing with the homebrew, but I don't really have any interest in the internet aspect, aside from finding a nice EG Browser HDD periphrial setup for the Jap 10k, without the SCPH10000 console included in the cost (I have 2 DTL-H10k's, I wont buy an SCPH10000 I so do not need, just for the goodies package, someone must have the stuff left after the console died, but 10k's are REAL SONY, built like tanks, cost $350 in Japan, and they don't go out so easily as exports, but I can wait) so I'll get it all and get into that when it just happens, then I'll be bugging you to cue me in on the whole internet trip.
say, though, the PS2 Reality Media Player 1.5 M/C Installer cd software has a homebrewed IP access trip in it that might be helpful to you, and I assume you've messed with "Pukklink", if not DO, those would be the programs I'd want to read the source code of, if I were into knowing about TCP/IP.
GOOD LUCK, and HAPPY CODE HACKING.
A toxic agent on a dangerous mission so secret, even I don't know what it is, because if I did, I would have to kill myself. I don't even know who's side I am on.