How to solve this after update laravel 8 to 9 Undefined constant Illuminate\Http\Request::HEADER_X_FORWARDED_ALL

When upgrading from Laravel 8 to Laravel 9, the constant Illuminate\Http\Request::HEADER_X_FORWARDED_ALL was removed because it was never officially defined in Laravel.

This was a common workaround in earlier versions, but it’s not supported in Laravel 9+.

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✅ What to do instead

In App\Http\Middleware\TrustProxies, update this line:

❌ Wrong (causes error in Laravel 9):

protected $headers = Request::HEADER_X_FORWARDED_ALL;

✅ Correct (Laravel 9+):

If you’re using all standard forwarded headers:

protected $headers = 
    Request::HEADER_X_FORWARDED_FOR |
    Request::HEADER_X_FORWARDED_HOST |
    Request::HEADER_X_FORWARDED_PORT |
    Request::HEADER_X_FORWARDED_PROTO;

Or to trust all forwarded headers (if you’re behind a trusted proxy):

protected $headers = Request::HEADER_X_FORWARDED_AWS_ELB;

HEADER_X_FORWARDED_AWS_ELB is a Laravel-defined constant that covers most AWS/ELB setups.

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🔒 Also ensure you set the correct proxies:

protected $proxies = '*'; // or ['127.0.0.1', '::1'] or specific IPs

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✅ Example of fixed TrustProxies class (Laravel 9):

namespace App\Http\Middleware;

use Illuminate\Http\Request;
use Fideloper\Proxy\TrustProxies as Middleware;

class TrustProxies extends Middleware
{
    protected $proxies = '*';

    protected $headers =
        Request::HEADER_X_FORWARDED_FOR |
        Request::HEADER_X_FORWARDED_HOST |
        Request::HEADER_X_FORWARDED_PORT |
        Request::HEADER_X_FORWARDED_PROTO;
}

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🔄 Summary

Issue	Fix
HEADER_X_FORWARDED_ALL	Use bitwise combination of valid headers
Laravel 9+ IP detection	Update TrustProxies accordingly

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Let me know if you want help choosing the right $proxies value for a specific server like Nginx, Cloudflare, or AWS.