I think it was in R6 we got the ability to set HTTP-headers on the site documents based on different rules.

While this is very powerful and can cut A LOT of requests from your domino server there seems to be a situation that IBM has forgotten.

If you set up a rule to cache everything in say the /fckeditor/* library the default web site rule only does the header addition for status code 200 and 206.

What that would mean is that after your number of days had expired the client would return back to validate if the content had changed with a 304 response back from the server.

This would occur EVERY TIME the page is requested and we get a hit to the server - ok it is not the whole content that needs to be returned but it is a hit none the less. Our caching rule is now working against us!

The solution is of course to include the 304 status in the response header rule.

See my example below.

The result would be that when the client returns - after 20 days - it would get another 20 days of cache and will not have to return back for a 304 every time the content is needed.

Don't forget where you heard this one from! I have learned this the hard way.