URL Policy

Do not Query Neighbors for URLs Containing

For URLs containing strings you add to this list, the Netra Proxy Cache Server looks in its own cache and does not query parent and sibling caches.

TTL Selection Based on URL

The Netra Proxy Cache Server enables you to set the TTL for URLs containing strings that you specify. You can specify the TTL in either of two ways: as an absolute value or as a percentage of an object's age. Entries have the following form:

<reg expression>
 <absolute TTL>
 <percentage>
 <maximum TTL>

where the variables mean the following:

<reg expression> is a regular expression that is matched against a URL. See "Rules for Pattern Matching for TTL Selection Property" for rules for the regular expression.

<absolute TTL> is the TTL (in minutes) used by the Netra Proxy Cache Server if the percentage method is not used.

<percentage> is the percentage of the duration between an object's last-modified timestamp and the current time.

<maximum TTL> is the upper limit (in minutes) on the TTL.

The proxy cache uses the percentage method of determining the TTL if a matched object has a last-modified timestamp. If an object does not have such a timestamp, the absolute TTL is used instead. You can specify a negative value for <absolute TTL> thereby forcing the percentage method to be used. If a matched object then does not have the required timestamp, the TTL is set from a value set under Cache Policy (see Step 1 under "Cache Policy").

If neither the absolute TTL nor percentage methods result in a TTL for a matched object, the TTL is determined from the values set in the Cache Policy properties.

The Netra Proxy Cache Server checks all patterns in the list and uses the last match.

An example of a TTL-selection entry:

^http:// 1440 20 43200

The preceding example matches URLs that start with http://. If a URL contains a last-modified timestamp, the TTL for that URL is set to 20% of the difference between the timestamp and the current time. If the URL does not have such a timestamp, the TTL is set to 1440 minutes. In any event, the URL will not stay in the cache longer than 43200 minutes.