os/modules/proxy/proxy.conf

## Headers
proxy_set_header X-Original-URL $scheme://$http_host$request_uri;
proxy_set_header X-Forwarded-URI $request_uri;
proxy_set_header X-Forwarded-Ssl on;

## Basic Proxy Configuration
client_body_buffer_size 128k;
proxy_next_upstream error timeout invalid_header http_500 http_502 http_503; ## Timeout if the real server is dead.
proxy_redirect  http://  $scheme://;
proxy_http_version 1.1;
proxy_cache_bypass $cookie_session;
proxy_no_cache $cookie_session;
proxy_buffers 64 256k;

## Trusted Proxies Configuration
## Please read the following documentation before configuring this:
##     https://www.authelia.com/integration/proxies/nginx/#trusted-proxies
set_real_ip_from 10.13.12.0/24;
set_real_ip_from fd00:b12f:acab:1312:acab::/80;

real_ip_header X-Forwarded-For;
real_ip_recursive on;

## Advanced Proxy Configuration
send_timeout 5m;
proxy_read_timeout 360;
proxy_send_timeout 360;
proxy_connect_timeout 360;