VPN

Your laptop is in a hotel. Your company's internal network is in Vienna. The Internet between them is untrusted, but you'd like your laptop to communicate as though it had a protected path into the corporate network.

A VPN creates a protected logical tunnel across another network. In this setup, it encrypts the original packets and wraps them inside new packets addressed to the company's VPN gateway, which decrypts and forwards them into the internal network.

Laptop
   ║
   ║ encrypted tunnel
   ║
Internet
   ║
Company network

Traffic entering the tunnel is protected and delivered to the remote VPN endpoint. When one person needs access from a laptop, a remote-access VPN connects that device to the company network. When two offices need to communicate, a site-to-site VPN connects their networks through VPN gateways.