So, here's how I fixed my strict NAT issue and some background info provided by Chthon.
Network Address Translation (NAT) is a method that enables Peer to Peer (P2P) connections like the one used for TL2. Your router has different NAT settings and these can affect your ability to play P2P games. Your NAT can be Strict, Medium, or Open. An unlimited number of people with Medium and Open NATs can play together. But, the problem comes with someone with a Strict NAT. If you have a Strict NAT you can only play with other players who have Open NATs. If anyone else has Strict or Medium NAT settings, you will suffer the well-known disconnects common to TL2's multiplayer.
So, here's how I fixed my NAT.
1)
Enable Port Forwarding on your Router.To do this:
-open the Command Line (CMD).
-type 'IPConfig', hit ENTER
-find the IPv4 address and the Default Gateway. Both of these are IP addresses. Here's an example of what that looks like (198.162.1.1)
-keep the CMD window open, you'll need to reference these IP addresses
-open your internet browser
-input the Default Gateway address into your html bar and hit ENTER, this should take you to your router login. If it doesn't, try routerlogin.net
-enter your ID and password. Usually it's 'admin/password' by default.
-find the Port Forwarding settings for your router
-set Port Forwarding to enabled and enable forwarding to the following TCP and UDP ports:
2)
Edit your local_settings.txt fileRunic suggests this might help your NAT and this is what worked for me.
https://support.runicgames.com/kb/articles/3-strict-nat-detected-go to your Torchlight 2 folder, usually USER/DOCUMENTS/MY GAMES/RUNIC GAMES/TORCHLIGHT 2/
-open local_settings.txt
-change the line UDPORT :0 to a port number within the ranged we opened for Port Forwarding on our router.
I don't know for sure, but I suspect it's best not to set it to the same port that TL2 already requires. You can see which ports those are here:
https://support.runicgames.com/kb/articles/27-network-port-requirementsIf someone knows more about this problem, please feel free to pitch in. If this works for you, let me know here. If it doesn't, let me know, too.