VPNs and IPSec Demystified
This article will give you enough background information to create an IPSec VPN on your FreeBSD box.
A VPN, or Virtual Private Network, is a cryptosystem that allows you to secure your data as it travels over an insecure network such as the Internet. While this may sound similar to the SSH cryptosystem, VPNs have a different purpose. SSH was designed to allow a user to login securely to and remotely administer another computer. A VPN is designed to allow a user to access transparently the resources of a network. As far as the user is concerned, she will be able to do anything she normally would be able to do, even when she is away from the network. Because of this, VPNs are popular with telecommuters and with offices that need to share resources over physically separate locations.
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