How does Geo IP Redirect determine IP address of website visitors?

How does Geo IP Redirect determine IP address of website visitors?

Our module retrieves users' IP address from the server header array, specifically from the following headers:

HTTP_X_REAL_IP
HTTP_CLIENT_IP
HTTP_X_FORWARDED_FOR

If none of these return a value, the module then uses Magento’s built-in getRemoteAddress method from the following class:

\Magento\Framework\HTTP\PhpEnvironment\RemoteAddress