No matter what I do, it seems like I cannot get my NAT type to stay open. I play on PC, and have two other PS3s. If I put my computer in DMZ, it will work along with my first PS3 but once more devices connect like the other PS3 and my mom's laptop and iPad the NAT goes back to either Moderate or Strict. Right now it's at Strict. I use an Arris Telephony modem from Comcast with a Linksys router along with an Ethernet Switch cause I have everything wired except my mom's laptop and needed more ethernet ports. What could be causing the problem here? Nothing I have found on Google has fixed my problem. I hope someone here can help?