Calvin Park wrote:
Hello squid users~ I am using on squid 3.1.4 , and I need to cache about 404 code. In squid 2.7 , there have rule like "refresh_pattern . 0 20% 4320 negative_ttl=xxx" When can I use negative_ttl syntax in squid 3.1 ?
negative-ttl=N is an option for Squid caching of helper process lookups and similar when the lookups can be cached.
Force-caching HTTP 404 pages is a very bad idea. It is done with a negative_ttl gobal option which caches ALL 4xx and 5xx pages which Squid receives. It extends an artificial DoS against all clients using the proxy if one single user hits a temporary upstream problem.
404 pages should come with useful cache-control expiry information that allows them to be stored for a short while anyway. No special action is required in the 3.1 to cache these HTTP-compliant pages for the proper time (unless you have negative_ttl set, in which case you need to remove it for their caching headers to work properly).
Amos -- Please be using Current Stable Squid 2.7.STABLE9 or 3.1.5
