Dear SQUID Community, it seems as if SQUID is not dealing correctly with "min-fresh" and "max-stale": Currently we are evaluating the use of SQUID-2.6-STABLE4. It all seems to work pretty well, but just "min-fresh" and "max-stale" is not working. Our client agent wants to guarantee to get data that is fresh for a specific amount of time. So we provide "min-fresh=3500" and "max-stale=0". To verify SQUID's behaviour we have programmed an origin server the always responds with some static headers and entity data, and a client that requests exactly that information, via SQUID as a proxy. The client uses the Cache-Control header with a min-fresh=3500 and max-stale=0 value, and the server is always sending data with a max-age=3600 value. But the client gets from SQUID a 200 OK response having max-age=3600 and Age=502! So, the current age of 502 plus the desired min-fresh of 3500 is 4002, minus the max-stale of 0 still is 4002, what is much more than the max-age of 3600 -- so the request cannot be satisfied without a warning, since the response will not be fresh long enough! So we expect to get at least a Warning header. But there is none! It looks like SQUID just ignores the min-fresh=3500 and max-stale=0 headers! The HTTP/1.1 specification says: 13.1.2 Warnings Whenever a cache returns a response that is neither first-hand nor "fresh enough" (in the sense of condition 2 in section 13.1.1), it MUST attach a warning to that effect, using a Warning general-header. also it says: 13.1.1 Cache Correctness If a stored response is not "fresh enough" by the most restrictive freshness requirement of both the client and the origin server, in carefully considered circumstances the cache MAY still return the response with the appropriate Warning header. In the default case, this means it meets the least restrictive freshness requirement of the client, origin server, and cache (see section 14.9) So for me it looks as if SQUID is buggy, since it does not add the mandatory Warning header. Can that be true? Or do I have to enable some switch like "HTTP/1.1-Compliance = YES"? Thanks! Markus
