There are several nodes in between nginx and apache. It's not internet -> nginx -> apache.

It's internet -> nginx -> varnish -> haproxy - > apache1
- > apache2
- > apacheN

So far, everything is in the apache access logs except the IP of the nginx server connecting.

But you're right, I could just set it manually, for each nginx server. I might just do that.

And you're also again right that our servers have multiple IPs.