1. Encrypted network connection within a TCP/IP connection Tunnel Vision creates a "virtual" TCP/IP network (VPN) between two Tunnel Vision-capable sites on the internet. It uses the strongest encryption that's actually useful (1024-bit RSA and 128-bit Blowfish) to protect your data along the way. This connection between two TV servers is called a "tunnel." Tunnel Vision is usually used on a router or gateway machine. When someone on your network wants to send data to someone on the other side of the tunnel, it sends through the default gateway (the TV server) like it normally would. You configure the TV server to send data through the tunnel instead of just forwarding it onto the internet. Tunnel Vision requires Linux 2.1.122 or higher with the ethertap and netlink devices. From Debian 3.0r0 APT