FreeS/WAN

FreeS/WAN is a Linux-based software that provides a highly secure implementation of IPSEC & IKE. IPSEC, which stands for Internet Protocol SECurity, is a protocol that uses strong cryptography to ensure both authentication and encryption services. These services are vital in building secure tunnels through untrusted networks by preventing unauthorised reading of packet contents and ensuring the packets are from the right sender and have not been altered in transit.

There are two main protocols used by FreeS/WAN; ESP (Encapsulating Security Payload) and IKE (Internet Key Exchange). ESP provides encryption plus authentication, while IKE negotiates connection parameters, including keys, for ESP. FreeS/WAN is made up of three main parts, namely KLIPS (kernel IPsec), which implements ESP, and packet handling within the kernel. Pluto, which is an IKE daemon, implements IKE and negotiates connections with other systems. Various scripts provide an administrator's interface to the machinery.

Because IPsec operates at the network layer, it is highly flexible and can be used to secure almost any type of internet traffic, but two applications are very widespread. The first being a Virtual Private Network (VPN), which allows multiple sites to communicate securely over an insecure internet by encrypting all communication between the sites. The second is "Road Warriors" who connect to the office from home, or perhaps from a hotel somewhere.

FreeS/WAN supports both of these applications, and various less common IPsec applications. However, it also adds an opportunistic encryption application, which is the ability to set up FreeS/WAN gateways so that any two of them can encrypt to each other, and will do so whenever packets pass between them. This is an extension that they are adding to the protocols. FreeS/WAN is the first prototype implementation, though they hope other IPsec implementations will adopt the technique once they demonstrate it.

In conclusion, FreeS/WAN is a highly flexible and powerful software that provides a secure implementation of IPSEC & IKE for Linux. Its ability to secure almost any type of internet traffic makes it a vital software in today's technologically advanced world. Its ease of use and ability to implement VPNs and other secure networks efficiently make it an excellent choice for individuals and businesses alike.