Hello, please help, my dad and I have always been able to hook up and play some racing sims. But, now we can not connect or even ping each other, it times out. We both have Charter ISP, and we both have XP SP2, with the firewall disabled. I have a router with the ports and DMZ setup. I called Charter they were no help at all. I have checked everything I could think of. If I create a server other people I don't even know connects with no problem, but my dad does not even see it in the list of games.
Again, also, now I can not ping him or him/me. Please HELP!
I'll cut and paste and ipconfig /all in here if someone will tell me how to get a dos windos to copy. Thanks,

Check in the router for something like "Enable WAN Response" or something like that. This lets the router respond to ping requests. Or, just check the manual for it. I am not sure that configuring your system to be the DMZ will still let ICMP through.

To copy and paste from a dos screen (command promt), just for interests sake:

Once you've done what you wanted in the command promt and you are ready to copy you need to right click anywhere on the black, in the popup menu click MARK, then you can use your mouse to drag a white box over all the writing you want to copy, once that is done you need to press ENTER, and thats it, then you can paste normally in your favorite word processing program.