php artisan make:auth

Route::group(['middleware' => 'web'], function () {
 Route::auth();
 Route::get('/home', 'HomeController@index');
});

<?php
return [
 'defaults' => [
  'guard' => 'web',
  'passwords' => 'users',
 ],
 'guards' => [
  'web' => [
   'driver' => 'session',
   'provider' => 'users',
  ],
  'admin' => [
   'driver' => 'session',
   'provider' => 'admins',
  ],
  'api' => [
   'driver' => 'token',
   'provider' => 'users',
  ],
 ],
 'providers' => [
  'users' => [
   'driver' => 'eloquent',
   'model' => App\User::class,
  ],
  'admins' => [
   'driver' => 'eloquent',
   'model' => App\Admin::class,
  ],
 ],
 'passwords' => [
  'users' => [
   'provider' => 'users',
   'email' => 'auth.emails.password',
   'table' => 'password_resets',
   'expire' => 60,
  ],
 ],
];

Route::group(['prefix' => 'admin' ,'middleware' => 'admin'], function () {
 Route::get('login', 'Admin\AuthController@getLogin');
 Route::post('login', 'Admin\AuthController@postLogin');
 Route::get('register', 'Admin\AuthController@getRegister');
 Route::post('register', 'Admin\AuthController@postRegister');
 Route::get('logout', 'Admin\AuthController@logout');
 Route::get('/', 'Admin\AdminController@index');
});

php artisan make:controller Admin/AuthController
php artisan make:controller Admin/AdminController

<?php
namespace App\Http\Controllers\Admin;
use App\Admin;
use Validator;
use App\Http\Controllers\Controller;
use Illuminate\Foundation\Auth\ThrottlesLogins;
use Illuminate\Foundation\Auth\AuthenticatesAndRegistersUsers;
class AuthController extends Controller
{
 use AuthenticatesAndRegistersUsers, ThrottlesLogins;
 protected $redirectTo = '/admin';
 protected $guard = 'admin';
 protected $loginView = 'admin.login';
 protected $registerView = 'admin.register';
 public function __construct()
 {
  $this->middleware('guest:admin', ['except' => 'logout']);
 }
 protected function validator(array $data)
 {
  return Validator::make($data, [
   'name' => 'required|max:255',
   'email' => 'required|email|max:255|unique:admins',
   'password' => 'required|confirmed|min:6',
  ]);
 }
 protected function create(array $data)
 {
  return Admin::create([
   'name' => $data['name'],
   'email' => $data['email'],
   'password' => bcrypt($data['password']),
  ]);
 }
}

<?php
namespace App\Http\Controllers\Admin;
use Illuminate\Http\Request;
use App\Http\Requests;
use App\Http\Controllers\Controller;
use Auth;
class AdminController extends Controller
{
 public function __construct()
 {
  $this->middleware('auth:admin');
 }
 public function index()
 {
  $admin = Auth::guard('admin')->user();
  return view('admin.home');
 }
}

<ul class="nav navbar-nav navbar-right">
     <!-- Authentication Links -->
     @if (Auth::guest('admin'))
      <li><a href="{{ url('/login') }}">Login</a></li>
      <li><a href="{{ url('/register') }}">Register</a></li>
     @else
      <li class="dropdown">
       <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-expanded="false">
        {{ Auth::guard('admin')->user()->name }} <span class="caret"></span>
       </a>
       <ul class="dropdown-menu" role="menu">
        <li><a href="{{ url('/admin/logout') }}"><i class="fa fa-btn fa-sign-out"></i>Logout</a></li>
       </ul>
      </li>
     @endif
    </ul>

return redirect()->guest($guard.'/login');