First, have your friends verify if they are running NAT type 2 as well. If someone is not, they will need to use the instructions provided by their routers manufacturer to change their NAT type. If that doesn't fix the problem then you will need to change the NAT type to 1. The easiest way to do this is to place your console in the routers DMZ but this can also be accomplished with port forwarding. Again, you will need instructions for your router to do this. We also recommend setting a static IP for your console.