Am too using Cloudflare and below are my IIS setings (somewhat illogical yet they seem to work OK for me):

Output Caching:
Prevent All Caching for .axd, .css, .gif, .jpg, .js and .png file both for User Mode Policy and Kernel-Mode Policy.

Edit Feature Settings:
- Enable cache
- Enable kernel cache
- Maximum cached response size (in bytes): 262144

 With these settings I get ff. Response Headers (for default.css):

CF-Cache-Status:     HIT
CF-RAY 2068753265901a87-DUS
Cache-Control public,
max-age=604800
Connection keep-alive
Date Wed, 15 Jul 2015 21:11:05 GMT
Etag "0805185f892d01:0"
Expires Wed, 22 Jul 2015 21:11:05 GMT (note here: cache is 7 days here which was set with Cloudflare)
Last-Modified Wed, 20 May 2015 12:28:48 GMT
Server cloudflare-nginx
Vary Accept-Encoding

Of course I don't claim the settings couldn't be tweaked or streamlined even more but as mentioned above - they work for me.

All of these assume that the crucial settings are also applied with Cloudflare.

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Tried the settings but still not getting the HIT for the cache. Cloud Flare support said that it was because my site is using cookies and to turn them off. Do you have and itesm set-cookie on your report? The hard part would be trying to find the modules that are using cookies.

Cloudflare support either don't know what they're saying or .... whatever.

If you examine this very page we're exchanging info in a web-browser dev tools console - I use Firebug in Firefox - then you'll see in the network tab that DNN Corp. also uses Cloudflare - perhaps on a business plan - and they have 20 cookies here.

My site uses 30 cookies and I have no problems with them on the Cloudflare's free plan.

DNN installs widely use cookies so I don't know what their support try to communicate to you.

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