A Virtual Private Network is private network of a company that uses shared lines to transfer the data using secure procedures and tunneling protocol.
A VPN uses public telecommunication lines to transfer data with privacy and at the same allowing all users of the company to share the data. VPN is a cost effective solution that more and more companies are looking forward to use as an Intranet too. The data transferred through is encrypted at the originating end and decrypted end. As an additional security measure, the originating and receiving addresses too are encrypted. Many newer operating systems like Windows 2000 support VPN.