The Sustainable Network

SSL

SSL VPNs are probably the most widely deployed VPN solutions for remote access and telecommuting. Instead of relying upon your networking knowledge to configure a client on your device, SSL VPNs use SSL/HTTPS as a secure transport mechanism, which just happens to be available on almost all standard web browsers. Using an SSL VPN, the connection between you and your destination resource happens via a web connection at the Application layer, as opposed to an IPSec VPN tunnel at the Network layer (see Chapter 31 and especially Figure 31-2 on the seven layers of the OSI model).

SSL VPNs are available wherever there is a standard web browser, and are independent of the underlying operating system of the device; this opens up the possibilities to a large variety of computing devices, such as smartphones. And it's very user-friendly. You do not need to configure or download anything onto the device prior to using it to access corporate resources. Most importantly, however, are the granular access controls that enterprises can use to ensure that users only see the resources and applications they are authorized to see. It's the biggest selling point of SSL technology, and this accounts for its popularity in small- to mid-size businesses. For example, your administrator can designate the URL, the files, and the server applications that you can access using the SSL VPN, thus mitigating the risks that an unprotected endpoint, untrusted network, or unauthorized user could introduce.

And because ...