Drupal 8 reverse proxy settings

settings.php

<?php

/**
 * Reverse Proxy Configuration:
 *
 * Reverse proxy servers are often used to enhance the performance
 * of heavily visited sites and may also provide other site caching,
 * security, or encryption benefits. In an environment where Drupal
 * is behind a reverse proxy, the real IP address of the client should
 * be determined such that the correct client IP address is available
 * to Drupal's logging, statistics, and access management systems. In
 * the most simple scenario, the proxy server will add an
 * X-Forwarded-For header to the request that contains the client IP
 * address. However, HTTP headers are vulnerable to spoofing, where a
 * malicious client could bypass restrictions by setting the
 * X-Forwarded-For header directly. Therefore, Drupal's proxy
 * configuration requires the IP addresses of all remote proxies to be
 * specified in $settings['reverse_proxy_addresses'] to work correctly.
 *
 * Enable this setting to get Drupal to determine the client IP from
 * the X-Forwarded-For header (or $settings['reverse_proxy_header'] if set).
 * If you are unsure about this setting, do not have a reverse proxy,
 * or Drupal operates in a shared hosting environment, this setting
 * should remain commented out.
 *
 * In order for this setting to be used you must specify every possible
 * reverse proxy IP address in $settings['reverse_proxy_addresses'].
 * If a complete list of reverse proxies is not available in your
 * environment (for example, if you use a CDN) you may set the
 * $_SERVER['REMOTE_ADDR'] variable directly in settings.php.
 * Be aware, however, that it is likely that this would allow IP
 * address spoofing unless more advanced precautions are taken.
 */
$settings['reverse_proxy'] = TRUE;

/**
 * Specify every reverse proxy IP address in your environment.
 * This setting is required if $settings['reverse_proxy'] is TRUE.
 */
$settings['reverse_proxy_addresses'] = array('a.b.c.d', ...);

/**
 * Set this value if your proxy server sends the client IP in a header
 * other than X-Forwarded-For.
 */
$settings['reverse_proxy_header'] = 'X_CLUSTER_CLIENT_IP';

/**
 * Set this value if your proxy server sends the client protocol in a header
 * other than X-Forwarded-Proto.
 */
$settings['reverse_proxy_proto_header'] = 'X_FORWARDED_PROTO';

/**
 * Set this value if your proxy server sends the client protocol in a header
 * other than X-Forwarded-Host.
 */
$settings['reverse_proxy_host_header'] = 'X_FORWARDED_HOST';

/**
 * Set this value if your proxy server sends the client protocol in a header
 * other than X-Forwarded-Port.
 */
$settings['reverse_proxy_port_header'] = 'X_FORWARDED_PORT';

/**
 * Set this value if your proxy server sends the client protocol in a header
 * other than Forwarded.
 */
$settings['reverse_proxy_forwarded_header'] = 'FORWARDED';