[Zope] How to pass IPs to Zope, when using Apache?

I'd like to use the REMOTE_ADDR key from all requests to my server, and I have Apache in front of Zope. Calling that key retrieves 127.0.0.1 as expected, given the fact Apache is currently the only one client to Zope, but this last should get to know the visitor's IP in order to perform tasks. What's the best way to do this? Ausum