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Re: Fact-checking: do any in-service proxy caches ever ignore Expires?

From: Kolics Bertold, University of Veszprem <bertold@tohotom.vein.hu>
Date: Sat, 15 Mar 1997 15:57:04 +0100 (MET)
To: Jeffrey Mogul <mogul@pa.dec.com>
Cc: http-wg@cuckoo.hpl.hp.com, http-wg@cuckoo.hpl.hp.com, Duane Wessels <wessels@nlanr.net>
Message-Id: <Pine.LNX.3.95.970315154002.25244C-100000@tohotom.vein.hu>

On Fri, 14 Mar 1997, Jeffrey Mogul wrote:
> Koen and I have been discussing offline whether it is possible
> to send
> 	Expires: Sun, 06 Nov 1994 08:49:37 GMT
> (or some similar ancient date) to ensure that *every* pre-HTTP/1.1
> proxy cache will not, under *any* circumstances, cache the response.
It *is* possible in Squid-1.1.x.
Excerpt from the Release-Notes:
"Squid 1.1 switched from a Time-To-Live based expiration model to a
Refresh-Rate model.  Objects are no longer purged from the cache when
they expire.  Instead of assigning TTL's when the object enters the
cache, we now check freshness requirements when objects are requested.
"

Minimum age can be given for specific URL patterns. By default it is set
to zero for all URL patterns, but for cache-unfriendly sites it is usually
changed...

HTTP/1.1's Cache-control: max-age=... is also implemented and as the
Release-Notes say "the Max-Age in a client request takes the highest
precedence" (when checking the freshness of a URL).

Bertold

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 Kolics, Bertold                             E-Mail: bertold@tohotom.vein.hu
 University of Veszprem, Hungary        W3: http://tohotom.vein.hu/~bertold/
 Information Engineering Course
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Received on Saturday, 15 March 1997 06:47:51 EST

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