Recently I started using Pound as a load balancer to a cluster of nginx servers and found my access logs were filled with the IP address of the load balancer. I did some digging and found the correct way to “fix” this.

First thing you need to do is make sure you remove X-Forwarded-For from Pound

ListenHTTP
    # ... snip ...
    # ... snip ...
    HeadRemove "X-Forwarded-For"
End

Once this is done, reload Pound.

Next you need nginx compiled with realip module - http://wiki.nginx.org/NginxHttpRealIpModule

On Ubuntu/Debian servers this module comes by default, otherwise you may have to compile it in yourself using the following option:

--with-http_realip_module

Once this is all done modify your nginx vhosts and add the following 2 lines

set_real_ip_from [IP];
real_ip_header X-Forwarded-For;

Where [IP] is the IP address of your load balancer.

To configure this to work with Apache you need the mod_rpaf module.