Setting up admin authentication in Laravel

To setup admin authentication, we need to simply create a middleware and use it in your routes.
Create a middleware using artisan

php artisan make:middleware Admin

This will create a new file called "Admin.php" in app/Http/middleware.
Add following code in handle method

$user = $request->user();
if(\Auth::guest())
    return redirect(route('admin_login'));
if($user && $user->user_type != 'a')
    return redirect(route('home'));
return $next($request);

Almost, there. Add your new middlware to app/Http/Kernel.php

protected $routeMiddleware = [
        'auth' => \App\Http\Middleware\Authenticate::class,
        'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,
        'can' => \Illuminate\Foundation\Http\Middleware\Authorize::class,
        'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
        'throttle' => \Illuminate\Routing\Middleware\ThrottleRequests::class,
        'admin' => \App\Http\Middleware\Admin::class, // Add this line
    ];

Notice, user_type will check if the user is an admin or not.

rajankur/admin_middleware_laravel.md

Setting up admin authentication in Laravel