IPsec (Internet protocol security) is a standardized framework for securing IP communications by encrypting and/or authenticating each IP packet in a data stream.
The IPsec standard is commonly used for establishing an IPsec VPN over the Internet between fixed end-points, as well as for creating an encrypted VPN client-server connection between remote devices and a fixed network. IPsec VPNs have largely been supplanted by SSL VPNs, such as the F5 FirePass SSL VPN, because they enforce end-point security, require no configuration on the remote machine, and apply security at the application layer instead of at the network layer. Security in the application layer alleviates typical configuration and implementation failures IPsec, which by design enforces security in the network layer and is functionally limited to usage on known and controlled networks.