CloudFlare acts as a reverse proxy and caches site content.
Is it possible to see my site's real IP address if I'm using a CDN like CloudFlare?
When I check my site's IP address using a lookup service, I get CloudFlare's IP address.
There are a few smart ways, so in theory it is sometimes possible, but only with a bad admin configuration. In practice it's about impossible.
For example, try getting the IP address of a site's DNS records like:
webmail.domain, etc... Maybe they'll point to the real IP address if they're not proxied through CloudFlare.
CloudFlare wasn't made for nothing - it's an anti-DDoS service and a CDN, which will also protect a website by protecting it's IP address.