Help changing ps3 nat to open?

Your NAT Type is determined on how well your Internet Connection is, there is no way to force this upon a connection. 'Open' provides sufficient connection for the rest of the lobby/group/etc. to "feed" off of, which is usually about ~24 different IP addresses max. The result of any other NAT Type you're getting is most likely a problem with your connection. Try resetting your router, not restarting, resetting. Then allow it to automatically optimize it's settings. Once finished, turn to your PS3 and go to Settings>Network Settings and go to Internet Connection Settings. From there, set everything to automatic, allow it's settings to correspond with your router's. Also, you never mentioned which connection type you're using, Wireless or LAN, some methods are different for each. I'm currently running Linksys with a wireless connection with no problems whatsoever on my PS3, and I have UPNP disabled, so I recommend disabling that aswell. Most of the time, UPNP is simply used for security reasons, which could only lag your gameplay. Save your settings after your done and run a connection test. After the test has completed check at the bottom of the results, at the Upload/Download Speed. If they don't display, then you'll have to manually set up your PS3 connection with your router. If they display, but are low packet results, then it is most defenitley your internet connection. Your Internet provider makes the largest difference on how well your Internet preforms, I recommend a better one if this continues.