I have 6 Nginx servers behind load balancer. Of course, if I just try to "deny" based on IP address it does not work as the app servers just see the load balancer IP.
However, I learned about the Real IP module and I have that enabled in the following way:
set_real_ip_from 0.0.0.0/0; real_ip_header X-Real-IP;
So, now that I have the X-Real_IP header set correctly, how I can then configure Nginx to use block certain users who's "X-Real-IP" value equals a set of IPs?