Hi I had also the Auth problem here my simple fix:
route add 18.104.22.168 mask 255.255.255.255 192.168.0.23 -p
route add 22.214.171.124 mask 255.255.255.255 192.168.0.23 -p
How I play NWN2 with mate:
1. Install game and install addon
2. Update with the update tool to the latest version
3. Download the miniImage
! It works for all versions.
4. Mount it via Daemon Tools
5. Install private server patch link
6. Execute the command at the top of my post to block the auth server from Atari but don' t' use as target ip "192.168.0.23" use some ip out of your local subnet.
7. Install Hamachi and open a network with your mate.
8. Go to adavanced und network properties at windows and bring the Hamachi interface at the top at the list, then NWN2 user the Hamachi interface by default.
8. Open NWN2 and click on Multiplayer
9. Type in some username and password (what ever there is no need to be valid)
9a. After a few seconds you get an error. This is ok go forward and you get a new menu for LAN etc.
10. Click on "New Game" and start the server.
11. Yor mate need to click on LAN or DirectConnect
12. Have Fun and buy the game if you like it.