Squid external overview

Refresh patterns
What is a refresh pattern?
A refresh pattern is a way of defining the expiry information for an object which does not have any expiry information, or overriding it when you know it is invalid

Generally used by people who really want to get the most of their cache

 #       'Min' is the time (in minutes) an object without an explicit
 #       expiry time should be considered fresh. The recommended
 #       'Percent' is a percentage of the objects age (time since last 
 #       modification age) an object without explicit expiry time
 #       will be considered fresh.
 #       'Max' is an upper limit on how long objects without an explicit
 #       expiry time will be considered fresh.
 #  refresh_pattern match min percent max [options]
refresh_pattern ^ftp:	 1440    20%     10080
refresh_pattern ^gopher:      1440    0%      1440
refresh_pattern .	     0       20%     4320