Hello @Crispin
The port you need to open in your router to allow external connections to Thinlinc is port 22 (SSH).
Regarding the message " Connection to server:“192.168.1.6” timed out. Check your settings." is due to fact that Thinlinc VSMServer will instruct your Thinlinc client to make a second SSH connection to the ipaddress of your server, which is 192.168.1.6.
Your client machine must have some way to directly make a connection to this address, and since it’s an internal address, we can work around this by utilizing an SSH tunnel and HOST_ALIASES.
@VirusABC has a great instruction for how he achived this, please see if you can make it work by reading
https://community.thinlinc.com/t/my-personal-thinlinc-use-case-and-some-performance-comparison/173#suggestions-6
With best regards,
Martin