Web Cache - Secure Computing SG300 User Manual

Web Cache

Note
SG565, SG575, SG580, SG635 and SG rack mount appliances only.
Web browsers running on PCs on your LAN can use the SnapGear unit's proxy-cache
server to reduce Internet access time and bandwidth consumption.
A proxy-cache server implements Internet object caching. This is a way to store
requested Internet objects (i.e., data available via HTTP, FTP, and other protocols) on a
server closer to the user's network than on the remote site. Typically the proxy-cache
server eliminates the need to re-download Internet objects over the available Internet
connection when several users attempt to access the same web site simultaneously.
The web site's contents are available in the cache (server memory or disk) and are
quickly accessible over the LAN rather than over the slower Internet link.
The SnapGear unit's web cache keeps objects cached in memory and, on a LAN network
share, caches Internet name (DNS) lookups and implements negative caching of failed
requests.
Using the lightweight Internet Cache Protocol, multiple web caches can be arranged in a
hierarchy or mesh. This allows web cache peers to pull objects from each other's
caches, further improving the performance of web access for an organization with
multiple Internet gateways.
The SnapGear unit's web cache may also be configured to pass off web transaction
requests or responses to a third-party ICAP server for processing, using its ICAP client.
This is typically used to integrate a third-party virus scanning, content filtering or complete
CSM solution, such as WebWasher (http://www.webwasher.com).
Enabling the web cache
Select Web cache under Network Setup. Check Enable to enable the web cache.
Selecting a cache size
Select the amount of memory (RAM) on the SnapGear unit to be reserved for caching
Internet objects. The maximum amount of memory you can safely reserve depends on
what other services the SnapGear unit has running, such as VPN or a DHCP server.
Network Setup
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