Historically, only large companies could afford secure networks, which they created from expensive leased lines. Smaller folks had to make do with the relatively untrusted Internet. Nowadays, even large companies have to go outside their private nets, because so many people telecommute or log in while they're on the road. How do you provide a low-cost, secure electronic network for your organization?The solution is a Virtual Private Network (VPN): a collection of technologies that creates secure connections or "tunnels" over regular Internet lines -- connections that can be easily used by anyone logging in from anywhere. A number of products now exist to help you develop that solution.This book tells you how to plan and build a VPN. It starts with general concerns like costs, configuration, and how a VPN fits in with other networking technologies like firewalls. It continues with detailed descriptions of how to install and use VPN technologies that are available for Windows NT and UNIX.Topics include:

• How the VPN compares to other available networking technologies
• Encryption, firewalls, and other technologies that let VPNs work
• VPN configuration (sample included)
• Point to Point Tunneling Protocol (PPTP) and Level 2 Tunneling Protocol (L2TP)
• The AltaVista Tunnel
• The Cisco PIX Firewall
• Maintenance and trouble-shooting
• Upcoming technologies like IPsec and S/WAN