Book Image

SSL VPN : Understanding, evaluating and planning secure, web-based remote access

Book Image

SSL VPN : Understanding, evaluating and planning secure, web-based remote access

Overview of this book

Virtual Private Networks (VPNs) provide remote workers with secure access to their company network via the internet by encrypting all data sent between the company network and the user?s machine (the client). Before SSL VPN this typically required the client machine to have special software installed, or at least be specially configured for the purpose. Clientless SSL VPNs avoid the need for client machines to be specially configured. Any computer with a Web browser can access SSL VPN systems. This has several benefits: Low admin costs, no remote configuration Users can safely access the company network from any machine, be that a public workstation, a palmtop or mobile phone By pass ISP restrictions on custom VPNs by using standard technologies SSL VPN is usually provided by a hardware appliance that forms part of the company network. These appliances act as gateways, providing internal services such as file shares, email servers, and applications in a web based format encrypted using SSL. Existing players and new entrants, such as Nokia, Netilla, Symantec, Whale Communications, and NetScreen technologies, are rushing our SSL VPN products to meet growing demand. This book provides a detailed technical and business introduction to SSL VPN. It explains how SSL VPN devices work along with their benefits and pitfalls. As well as covering SSL VPN technologies, the book also looks at how to authenticate and educate users ? a vital element in ensuring that the security of remote locations is not compromised. The book also looks at strategies for making legacy applications accessible via the SSL VPN.
Table of Contents (14 chapters)
SSL VPN
Credits
About the Authors
Introduction
A Review of TCP, IP, and Ports

Reverse Proxy Technology


The most basic function of an SSL VPN is its ability to receive user requests and relay them to internal servers. This gateway-type function is called reverse proxying.

Technically speaking, a reverse proxy server is a computer that sits between an internal web server and the Internet and appears to external clients as if it were the true web server. External users address the reverse proxy thinking that it is servicing their requests, when in reality it simply relays their requests to a different server usually situated on the internal network. Responses work in a similar manner—the true server responds to the reverse proxy, which in turn relays the response to the user. Reverse proxies are often deployed as part of load-balancing schemes, as part of a layered security strategy, or simply to hide real servers from users for security reasons.

Reverse proxies, as seen in the diagram overleaf, serve as entry points into an organization's web infrastructure.

Web reverse...