I run 4 domains on CloudFlare and found that 2 of my domains have a problem. Subdomains are not proxied somehow by CloudFlare. I run 2 websites realized with WordPress and 2 realized with Drupal. Somehow I can not proxy the subdomains for the Drupal websites. For the WordPress websites it works somehow.
I dont wat that anybody on the internet can reveal the origin IP of my servers. Thats why its important to proxy also the subdomains. Otherwise hackers can simply bypass the CloudFlare firewall.