Administrator's Guide - Kerio Software Archive

9.5 HTTP cache
Note: The configuration script requires that the proxy server is always available (even if
the Direct access option is used).
Allow browsers to use configuration script automatically...
It is possible to let Internet Explorer be configured automatically by the DHCP server. To
set this, enable the Automatically detect settings option.
Kerio Control’s DHCP server must be running (see chapter 9.2), otherwise the function will
not work. TCP/IP parameters at the host can be static — Internet Explorer sends a special
DHCP query when started.
Hint:
This method enables to configure all Internet Explorer browsers at all local hosts
by a single click.
9.5 HTTP cache
Using cache to access Web pages that are opened repeatedly reduces Internet traffic (in case of
line where traffic is counted, it is also remarkable that using of cache decreases total volume
of transferred data). Downloaded files are saved to the hard drive of the Kerio Control host so
that it is not necessary to download them from the web server again later.
All objects are stored in cache for a certain time only (Time To Live — TTL). This time defines
whether checks for the most recent versions of the particular objects will be performed upon
a new request of the page. The required object will be found in cache unless the TTL timeout
has expired. If it has expired, a check for a new update of the object will be performed. This
ensures continuous update of objects that are stored in the cache.
The cache can be used either for direct access or for access via the proxy server. If you
use direct access, the HTTP protocol inspector must be applied to the traffic. In the default
configuration of Kerio Control, this condition is met for the HTTP protocol at the default port
80 (for details, see chapters 7.3 and 15.3).
To set HTTP cache parameters go to the Cache tab in Configuration → Content Filtering →
HTTP Policy.
Enable cache on transparent proxy
This option enables cache for HTTP traffic that uses the HTTP protocol inspector (direct
access to the Internet).
Enable cache on proxy server
Enables the cache for HTTP traffic via Kerio Control’s proxy server (see chapter 9.4).
HTTP protocol TTL
Default time of object validity within the cache. This time is used when:
• TTL of a particular object is not defined (to define TTL use the URL specific settings
button —see below)
• TTL defined by the Web server is not accepted (the Use server supplied Time-To-
Live entry)
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