A standards-based security suite that operates transparently and may eliminate the need for proprietary firewall mechanisms in some applications. IPsec also provides for encapsulation of the secured IPv6 packets inside IPv4 datagrams, in consideration of both the increasing need for security and the long-term transition process to IPv6. IPsec is described in IETF RFC 2401 and, in the context of the OSI Reference Model, runs at the Network Layer (Layer 4). See also datagram, encapsulate,, firewall, IETF, IPv4, IPv6, Network Layer, OSI Reference Model, and packet.
(IP SECurity) A security protocol from the IETF that provides authentication and encryption over the Internet. Unlike SSL, which provides services at layer 4 and secures two applications, IPsec works at layer 3 and secures everything in the network. Also unlike SSL, which is typically built into the Web browser, IPsec requires a client installation. IPsec can access both Web and non-Web applications, whereas SSL requires workarounds for non-Web access such as file sharing and backup. IPsec is supported by IPv6. Since IPsec was designed for the IP protocol, it has wide industry support for virtual private networks (VPNs) on the Internet. See virtual private network, IKE, IPv6 and security protocol.