Public IP not showing correctly?

I know exactly how frustrating it is to be at your wit's end trying to debug intermittent IP issues – been there with campaign tracking and it's a hair-pulling experience!

• First, double-check for any *other* layers of reverse proxy or load balancing *before* your Nginx server. This could be an internal load balancer, a Docker network, Varnish, or even a firewall appliance. If Nginx is receiving traffic from another internal proxy, you might need to adjust your set_real_ip_from directives to include that internal proxy's IP range, and then ensure real_ip_recursive on; is active to correctly trace the original client IP through multiple hops. This is critical for proper reverse proxy configuration.
• Your PHP script needs a robust method to retrieve the client IP, checking for various HTTP headers in a specific order. Always prioritize HTTP_CF_CONNECTING_IP (if Cloudflare is active), then fall back to HTTP_X_FORWARDED_FOR (checking for multiple IPs if comma-separated), and finally REMOTE_ADDR. A common approach for parsing these HTTP headers looks like this:

  
  function getClientIP() {
      $ip = '';
      if (isset($_SERVER['HTTP_CF_CONNECTING_IP'])) {
          $ip = $_SERVER['HTTP_CF_CONNECTING_IP'];
      } elseif (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
          $ip = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR'])[0]; // Get the first IP
      } elseif (isset($_SERVER['REMOTE_ADDR'])) {
          $ip = $_SERVER['REMOTE_ADDR'];
      }
      return filter_var($ip, FILTER_VALIDATE_IP) ? $ip : 'UNKNOWN';
  }
  

  This helps with reliable What is my IP Address functionality.
• Intermittent `HTTP_CF_CONNECTING_IP` issues can sometimes stem from Cloudflare's own network routing (though rare) or caching layers. Ensure your Cloudflare firewall rules aren't inadvertently modifying or stripping headers for certain requests. Also, consider using a service like IPify or WhatIsMyIP.com's API as an external validation point for comparison.

Are you running any other services or containers on that Ubuntu 22.04 server that might be acting as an intermediary proxy?

Thanks for the detailed breakdown. Regarding the robust PHP method for client IP retrieval, I'm already using similar logic that prioritizes `HTTP_CF_CONNECTING_IP`. The puzzling thing is, even when Cloudflare is actively proxying the traffic, that header is still often completely absent or holds an incorrect value, which wasn't what I'd expect if it was reliably present.