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I found information that Internet Explorer 5 or maybe IIS 4.0 introduced support for the pre-check and post-check Cache-control headers. I haven't been able to find much info on if they are still supported in later versions such as IE 8, 9, 10 & 11.
I want to remove support for them in an application but want data that they are no longer used.
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Without the cache control header the browser requests the resource every time it loads a new(?) page.
Additional HTTP Cache Headers The expires header is ignored when a cache-control header containing a max-age directive is present.
Expiration is the caching mechanism by which a client can entirely avoid making requests to the origin server. When the origin server specifies an explicit expiration time in the resource, a cache can check that expiration time and respond accordingly without having to contact the server first.
Cache-ControlThis is probably the most important header when it comes to security. There are a number of options associated with this header. Most importantly, the page can be marked as "private" or "public". A proxy will not cache a page if it is marked as "private".
According to the replies on your tweet from the people that know what they're talking about, the pre-check and post-check headers may be supported, but their use is discouraged.
(just posting for posterity)
Yeah, short answer is that nobody should use these and all uses of "p*check=0" are junk.
I left p*check support in WinINET in the IE9 rewrite & I doubt removed since, but urge you to not use.
~ Eric Lawrence, Internet Explorer engineer who wrote the pre-check/post-check header code
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