in a nutshell, this step is just part of exploiting a trust relationship between two boxen (aka computers) that are on the net or simply communicating via a tcp based connection. what it does is fake out the other boxes on the network so they think that you're someone you're not.

i would go into further detail on this, but i'd take up too much space and probably get yelled at.

so if ya wanna find out more about it, you can go here: http://www.2600.com/phrack/p48-14.html
you can also check out the spoofing node.

ps. don't go and do something stupid. the purpose of these magazines are too inform you what can be done, so you can protect against it. in short, if you go and hack someones network, and end up branded, shot, arrested, court-martialed, drawn and quartered, drawn and halved, or run off by wild horse then it's not my fault. other than that, have fun!!

pps. it's highly unlikely that this will be accomplished from a box running windows, period.