There are many challenges that derive from the use of network address translation. These hurdles come from the fact that a computer presents itself to the outside internet world not as its own IP address, but rather that of the firewall device that is acting as the traffic cop for all computers that live on the network that sits behind it. Its IP address is the one that remote computer systems will see as you make a connection with your PC. If you are attempting vpn traversal, this can interfere with the connection process to the remote system as the data can require an independent address to send packets back to your system in order to create a secure tunnel connection. The process of vpn traversal involves the modification of configuration choices or the creation of workarounds to help the remote system to be able to use vpn traversal to overcome the problem of your private IP address not being directly routable from the outside network. There are firewall configuration choices that can enable access to some vpn traversal methods. There is also a way to statically map a live IP address that the firewall can host and respond to and forward directly to your computer, allowing vpn traversal by providing a real IP address for the outside vpn connection to bind to. There are other challenges that NAT can present beyond vpn traversal issues, but in all the advantages to such a structure far outweigh the inconveniences presented by a few people with vpn needs having a problem with vpn traversal. This is particularly true in light of the methods of enabling vpn traversal through a few configuration changes. Without the ability to use network address translation, there would literally be a shortage of valid, non-private IP addresses for the global community of computers, cellular phones, game consoles and the massive plethora of internet connectable devices.