It uses Unix pseudo terminals to wrap up subprocesses transparently, allowing the automation of arbitrary applications that are accessed over a terminal. It works with interactive applications such as telnet, ftp, passwd, fsck, rlogin, tip, ssh, and many others. Supported connection types are Remote Desktop, VNC, SSH.
No hacky approach using external applications! Tunneling support in Royal TSX is tightly integrated.
The Secure Gateway implementation is based on SSH tunnels (port forwarding) which is an industry standard for secure communication between systems.