Openswan is an implementation of IPsec (IP Security). Is it a code continuation of the defunct FreeS/WAN project. Openswan provides IPSEC kernel extensions (for encryption and authentication) and an IKE daemon (for Internet key exchange and encrypted routing), as well as various rc scripts. It features Opportunistic Encryption, subnet extrusion, X.509 certificates, NAT Traversal support, XAUTH, Enterprise L2TP, and DNSSEC support. Currently, work is being done with asynchronous crypto hardware accelerator support and a Mac OS X port.