A Virtual Private Network (VPN) provides a secure connection between two or more computers or protected networks over the public Internet. It provides authentication to ensure that the information is going to and from the correct parties. It provides security to protect the information from viewing or tampering en route.
Prior to the invention of Internet Protocol Security (IPsec) and Secure Socket Layer (SSL), secure connections between remote computers or networks required a dedicated line or satellite link. This was both inflexible and expensive.
A VPN creates a connection with similar reliability and security by establishing a secure tunnel through the Internet. Because this tunnel is not a physical connection, it is more flexible--you can change it at any time to add more nodes, change the nodes, or remove it altogether. It is also far less costly, because it uses the existing Internet infrastructure.
For information on configuring VPNs in SonicOS, see the following sections: