Many many people are having trouble with online, as nobody joins their free roam or matches.
Well, I have a solution.
Note: It varies on the router type, and I cannot be held responsible if your Router screws up. Also, I'm not sure if this will work on XBox
Okay first off if you know your PPoE username and password you can skip this part.
Type http://192.168.1.254/ into your web address. This should take you to your router.
Go into configure/option (You may need to enter "Expert mode" to get to this option)
Go into "Connection"
There may be a list of various things.
One of these might be the PPoE username and password. Username is an email address.
Take these down/edit if neccessary.
Check your Uppn
Restart router
Next step:
Go to your PS3 Network options
Select internet settings.
Choose custom.
Enter SSID and privacy things.
When it comes to IP, select "PPoE"
Put in your Username and password, then select auto for all others, with Proxy off and UPPN as it is on your server
Sign in, and check your settings.
Check your NAT type
If it is 1, then well done!
Internet fixed!