My current NET setting is Moderate, how do I change it to open? I believe you can do this without buying fancy gear.

Dude, Arran explained it. Go to www.whatismyip.com copy and paste your ip address into the URL bar up above... You're going to have to figure out the username and password to your router, but in most cases they can be found online by typing in your router model and whatnot on google. Then you should get to your router's settings. Currently my NAT type is Open, but I still get a message when playing Halo that my NAT type isn't compatible or something. It doesn't seem to affect gameplay at all but I'm looking here and under where it give me the option to enable or disable NAT (I have it set to enable) there is another option where it says "mode" and give me the choices of "Dynamic NAPT (currently selected), NAT and NAPT. What does this mean specifically?

I hope I answered your question well enough to justify asking one of my own, Tut.

Wut, NET != NAT. what exactly do you need help with, you haven't exactly given much information.

He means NAT.