Cache-control directive

I have a small server side include on my static pages that we use to log
visits to the site. A couple of months ago the number of visitor sessions
from the web logs (using webtrends) carried on at about the same rate, but
the number recored by my Server Side Include dropped by about 40%.

I suspect some proxy cache somewhere has kicked in in some way.

I need to basically make sure that html pages don't get cached by proxy
servers. I am not so fussed about browsers because I don't care if a user
looks at a page 20 times. I am not trying to artifically inflate our hits
figure, just get better information.

My first attempt was to try and set the expiry date on html files to be a
few seconds after the page is requested. But (see my other post) I can't
get that to work JUST for html files.

If I use the cache-control directive, (as I understand it) the best I can do
is to force a cache to revalidate the page with the server. However as the
html page with the server side include is unchanged, does that mean that
Apache will tell the proxy to go ahead and use its cached copy?

The SSI at present dosn't actually put anything on the page. If I got it to
place something unique (like the time) on the page would that be classed as
a changed page or does apache just look at the file information.

This seems like it should be a common problem but I can't seem to find
anything specifically about this issue. Does anyone have any ideas.

Bob

I have just found

Cache-Control: private

which would seem to be exactly what I need.

However would still be interested in the answers to my questions.

Bob