HP Cache Server Appliance Administrator Guide

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Appendix B Traffic Manager Configuration Options
Internet Explorer
requests force a check
with the origin server
Certain versions of Microsoft Internet Explorer do not request cache reloads
from reverse proxies and transparent caches when the user presses the browser
Refresh button. This can prevent content from being loaded directly from the
origin servers. You can configure Traffic Server to treat Microsoft Internet
Explorer requests more conservatively, providing fresher content at the cost of
serving fewer documents from cache. The following options are available:
never = never force a freshness check with the origin server
for IMS revalidation requests = only force a freshness check for IMS (If
Modified Since) revalidation requests
always = always force a freshness check with the origin server
Variable Content
Do not cache Some origin servers answer requests to the same URL with a variety of objects.
The content of these objects can vary widely, according to whether a server
delivers content for different languages, targets different browsers with
different presentation styles, or delivers variable content at different times of
the day.
You can set the Traffic Server to refuse to cache objects served in response to
URLs that contain a question mark, a semi-colon, cgi, or end in .asp.
Enable Alternates Configures Traffic Server to cache alternate versions of HTTP documents.
Va r y o n t he s e H T T P
header fields:
Using document header information, Traffic Server can compare cached
document specifications against requested specifications to determine if the
correct alternate version of the document is in the cache. For example, a
document header can specify that the document targets a specific browser, but
any browser can request the document from Traffic Server. If a requested
document’s fields do not match a cached document’s fields, the Traffic Server
does not serve the document from its cache, and instead retrieves a fresh copy
from the origin server.
If you select the Enable Alternates option, you can specify values to match for
the following fields:
If the request is for text = The default value is
user-agent and cookie
NOTE:
Some documents can have thousands of alternate cookie versions. If
you choose to vary on cookies, HP recommends that you limit the number of
alternates cached. See Storage‚ on page 135.
If the request is for images = Images are rarely personalized.
If the request is for anything other than text or images.
Cache responses to
requests containing
Cookies for:
You can configure Traffic Server to cache responses to requests that contain
cookies for:
• No content-types
• All content-types
• Only image-content types
• Content-types which are not text
Option Description