Virtual Private Network (VPN) is a communication network which provides secure data transmission in an unsecured or public network by using any combination of technologies. A virtual connection is made across the users who are geographically dispersed and networks over a shared or public network, like the Internet. Even though the data is transmitted in a public network, VPN provides an impression as if the data is transmitted through private connection. This paper provides a survey report on VPN security and its technologies.