TABLE OF CONTENTS Until recently, companies that wanted to provide remote access to the corporate network used an IPSec VPN concentrator. Connecting computers ran VPN client software to establish an encrypted tunnel to the concentrator. This worked well for many years (IPSec was first standardized in 1995 in RFC 1825) and IPSec proved to be a good way to create both site-to-site and remote access virtual private networks (VPNs).
As time passed, however, the traditional IPSec VPN became more difficult to deploy and maintain. Remote workers and corporate IT managers faced a rising tide of problems with IPSec, including:
New types of endpoints began to emerge. Since the IPSec VPN required client software, each new device required a new client. Modern remote workers need the flexibility to build VPNs from any endpoint, including pocket PCs and mobile phones.
As Internet broadband popularity ballooned, so did the security requirements needed to keep the network safe. Firewalls (blocking ports and performing address translation) and other network access devices (such as proxy servers) posed serious challenges to building a successful VPN, frustrating both remote workers and IT support personnel.
VPN access is no longer considered "nice to have." Years ago in many organizations, only a few traveling workers were allowed remote access and their expectations were low because VPN was compared to dial-up access. This has completely changed. In a growing number of organizations, nearly everyone has VPN access and it is now considered critically important.
The difficulty of deploying and maintaining client software has...
