NAT stands for Network Address Translation. It is, roughly speaking, a method of directing the traffic coming from the Internet - whether it's from a website, a game server or a P2P network - to the right device - computer, console, tablet, etc. - on your local network. Since this method takes into account both the device and the origin of the traffic engaged in the 'conversation', you can very well have an open NAT type for some services or game, and a closed one for others.
The piece of hardware responsible for NAT on a local network is the router. While other factors might negatively impact your NAT, your first step to troubleshoot NAT related issues should be to check your router configuration.
This last piece of information can be good news, or not:
- If you are using a shared internet connection in a communal building - dorm, military base, hospital, etc. - you might not have access to the router
- Some ISP might ostensibly provide you with a router, but put you behind a second router-like device that you do not have access to (your router is then not directly connected to the internet, but to a second 'local' network. This scenario is called Double NAT)
Now, to the troubleshooting!
We have put together connectivity troubleshooting FAQs to assist for most Ubisoft games. To find them, click on the How can we help? search bar at the top of this FAQ, select your game and your platform then type connectivity. An article relevant for your game will pop up with relevant troubleshooting steps to open your NAT and solve other connection-related issues.