Linux FreeS/WAN is an implementation of IPSEC & IKE for Linux.
IPSEC is Internet Protocol SECurity. It uses
strong cryptography to provide both authentication and encryption
services. Authentication ensures that packets are from the right
sender and have not been altered in transit. Encryption prevents
unauthorised reading of packet contents.
These services allow you to build secure tunnels through
untrusted networks. Everything passing through the
untrusted net is encrypted by the IPSEC gateway machine and
decrypted by the gateway at the other end. The result is
Virtual Private Network or VPN. This is a
network which is effectively private even though it includes
machines at several different sites connected by the insecure
The IPSEC protocols were developed by the IETF (Internet Engineering
Task Force) and will be required as part of IP Version Six, the next
generation. They are also being widely implemented for IP V4. In
particular, nearly all vendors of any type of firewall or security
software have IPSEC support either shipping or in development. There
are also several open source IPSEC projects. Several companies are
co-operating in the Secure Wide Area Network (S/WAN) project to
ensure that products will interoperate. There is also a VPN Consortium fostering cooperation
among companies in this area.
Our project's primary objective is to help make IPSEC widespread by
providing source code which is freely available, runs on a range of
machines including ubiquitous cheap PCs, and is not subject to US or
other nations' export restrictions.