Guys, i think that what he really wanted to know is how to start hacking with IP's and shit stuff like that, but there is another topic here on this board in which the same question was asked or at least close to that and i remember that we've explained it pretty good so no need to ask the same thing again, i believe this is the most asked question in every board in the internet:
-"I know the IP of the computer, how can i hack into it ?" and stuff like that.
That was explained, DaMaRiS no offense, i'm not saying you're a newb or anything else, if you are there's nothing to be shy from, nobody is born an EXPERT, everyone learns to achieve knowledge. You said you read a lot of tutorials and so on, well i suggest you continue...
Now asteos explained to you how TCP/IP layers, but i'd suggest you to learn first about the OSI layers which are maybe older but they're much easier to undestand the full things how it works, coz things there are more separated and you've got more details. Here i'll give you a short description of the OSI reference model.
2. DATA LINK
here a good link for you to read a bit more... The OSI Seven Layers Model
If you want more details about this one or anything else, just let me know ...
btw: SR that was a great explanation