Those products use SSL as the security mechanism to protect data (versus IPSec for traditional VPNs). The advantage of these products is that corporate information resources can be accessed from any PC with a web browser and Internet access. A SSL session is setup from the PC/browser back to the vendor's product, which is located behind the corporate firewall. The disadvantage is that these products do not support all applications used in a corporation. Whether they are completely secure is yet to be seen as they have not be widely deployed but most of these vendors state that security is a key element of their product.
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