Cloudflare has no effect on AdSense (at least in my experience), and you shouldn't need to install anything on the server.

Do I have to install mod_cloudflare?

Cloudfare has this **Notes:**
We would also strongly recommend installing mod_cloudflare so original visitor IP is passed back to your server logs.

Is mod_cloudflare necessary?

I had to have my hosting company install mod_cloudflare - as all my logs were just showing same IP addresses visiting my sites.

Once mod_cloudflare was installed - correct user IP addresses were coming in again.

I wanted to make sure adsense was seeing all the IPs and not just thinking same IPs were clicking the ads.

I don't think that's how it works. Without mod_cloudflare, only the server log is seeing the same ip. But Adsense is still seeing different ips. That's why mod_cloudflare is not necessary. Am I correct?

Anyone using cloudflare without mod_cloudflare installed?

mod_cloudflare is not necessary for Adsense, it only rewrites the local apache logs with the right IP addresses. Adsense always sees the customer IP.

Thank you!

I was using cloud flare for about 6 months. The past month I noticed irrelevant ads and numerous blanks spaces. I have since disabled Cloudflare and jumped back on original nameservers. My CTR is up 300% since getting rid of this CDN