By
enabling the caching service on an ISA server, many organizations have realized improved
access times for web and FTP services, while effectively increasing the available bandwidth
of the Internet connection at the same time.
The concept of web and FTP caching in ISA Server 2006 is fairly straightforward. All
clients configured to use ISA for caching send their requests for web pages through the ISA
Server, similar to what is shown in Figure 1.4. If it is the first time that particular page has
been opened, the ISA Server then goes out to the Internet, downloads the content
requested, and then serves it back to the client, while at the same time keeping a local
copy of the text, images, and other HTTP or FTP content. If another client on the network
requests the same page, the caching mechanism delivers the local copy of the page to the
user instead of going back to the Internet. This greatly speeds up access to web pages and
improves the responsiveness of an Internet connection.
22 CHAPTER 1 Introducing ISA Server 2006
NOTE
An added advantage to using ISA Server 2006 as a content-caching server is that all of
the HTTP traffic that clients request is scanned for exploits and viruses as well, decreasing
the threat of clients being infected with spyware, viruses, and other scumware.
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