Add X-Forwarded-For

[Sander Klein]

Hi,

I want to move some websites behind cloudfare. They already add an 
X-Forwarded-For header so I do not want to add it if the request comes 
from cloudfare, but I do want to add it if the request is not from 
cloudfare.

Since both requests will pass through the same frontend I need some 
kind of ACL or whatever.

Is there a way to do this?

Greets,

Sander