IPsec
Internet Protocol Security (IPsec) is a set of extensions to the traditional Internet Protocol (IP). IPsec ensures that communication in IP networks is secure. The extensions provided by IPsec encrypt and authenticate the data that is transmitted over the Internet Protocol. Since the IP network is insecure on its own, IPsec provides protection within the IP network as an additional step. With transport mode and a tunnel mode, Internet Protocol Security has two effective mechanisms. Transport mode establishes a point-to-point connection directly, while tunnel mode establishes a secure tunnel connection via two gateways.