A Virtual Private Network (VPN) allows the provisioning of private network services for an organi-zation over a public network such as the Internet. In other words a VPN can transform the characteristics of a public which may be non-secure network into those of a private secure network through using encrypted tunnels. In this book we introduce a survey on the following basic topics: 1) The VPNs evolution, standard terms, and common use. 2) VPN set of protocols. 3) Threats facing VPNs and security concepts. 4) The security technologies used in VPNs such as authentication, encryption, key management, digital signatures, and digital certificates. 5) VPN commercial products. 6) Nowadays VPN usage. Finally, in this book, we introduce a research work in order to customize a standard VPN to a newly one called EEVPN (Effective Extensive VPN). It transmits a small data size in through a web based system in a reasonable time without affecting the security level. The proposed EEVPN is more effective where it takes small data transmission time with achieving high level of security. Also, the proposed EEVPN is more extensive because it is not built for a specific environment.