Tunnel Connections options allow the computer running ISL AlwaysOn to accept tunneled connections (RDP, SSH or custom) and additionally pass them through to other computers in the local network.
Uncheck the "Use default server settings" option and check the "Allow Tunnel Connections (RDP,SSH)" option to allow tunneled connection to and through this computer.
The functionality of Tunneled connections is described in depth here: Tunneling
Hosted license users: by default "Allow Tunnel Connections (RDP, SSH)" is disabled. To enable it, uncheck "Use default server settings" and check "Allow Tunnel Connections (RPD, SSH).
Server License: System administrators may choose the "Default server settings" for "Allow Tunnel Connections (RDP, SSH)" in ISL Conference Proxy configuration pages.