Reverse Proxy Header

This module is the simplest way to use the specific HTTP header name to determine the client IP.

The module provides an equivalent of reverse_proxy_header setting (which is deprecated from Drupal 8.7.0).

The most common usage is:

• real client IP is stored in some custom (non-default) header;
• you cannot affect this on reverse proxy or server sides.

The module does not provide any UI. How to use it:
Step 1) Install the module via composer and enable it.
Step 2) Add the `reverse_proxy_header` configuration to your setting.php file:

/**
 * Sets the HTTP header name which stores the real client IP.
 *
 * @see https://www.drupal.org/project/reverse_proxy_header
 */
$settings["reverse_proxy_header"] = "HTTP_X_FORWARDED_FOR_CUSTOM_HEADER";

Here is an example for setting.php file to configure the module to use Cloudflare header only for some instances:

/**
 * Reverse Proxy Header module configuration.
 *
 * Determines the specific header name for some environments only.
 * And skips for others.
 *
 * @see https://www.drupal.org/project/reverse_proxy_header
 */
if (getenv("ENVIRONMENT_SPECIFIC_VARIABLE") === "value") {
  $settings["reverse_proxy_header"] = "HTTP_CF_CONNECTING_IP";
}

What about available alternatives?

1. rename the header name (or copy its value) to the supported header HTTP_X_FORWARDED_FOR on proxy or server side;
2. copy the value from the custom header to $_SERVER['HTTP_X_FORWARDED_FOR'] in your index.php before Drupal initialization;

🇺🇦