auth.php

<?php

return array(

    'driver' => 'auth-ldap',
    'reminder' => array(
        'emails.auth.reminder', 'table' => 'password_reminders',
    ),
	// Ldap server
	'ldap'	=> 'UPDATE'
	'ldap-domain' => 'UPDATE'

);

global.php

<?php


Auth::extend('auth-ldap', function() {
	return new Illuminate\Auth\Guard(new LdapProvider, App::make('session.store'));
});

LdapProvider.php

<?php 

use Illuminate\Auth\UserProviderInterface as UserProvider;
use Illuminate\Auth\UserInterface as UserInterface;

class LdapProvider implements UserProvider{

	public function __construct(){}

	/**
	 * @param  string $identifier - ldap username
	 * @return User
	 */
	public function retrieveByID($identifier)
	{
		return new User(array('username' => $identifier));
	}

	/**
	 * [connectLdap description]
	 * @param  array  $credentials - passes in username / password
	 * @return boolean
	 */
	public function connectLdap(array $credentials)
	{
		$ldap   = ldap_connect(Config::get('auth.ldap'));
		$domain = Config::get('auth.ldap-domain', false );
		$domain = ( $domain ) ? "{$domain}\\" : '';
		
		/**
		 * If the username and password is not @ least 3 chars ...
		 * Prevents ldap_connect with password = abc
		 */
		if(strlen($credentials['username']) < 3 || strlen($credentials['password']) < 3){
			return false;
		}

		// If connection succeeds, then user is valid
		// ldap_bind fails hard with invalid credentials so let's silence it with @
		try { 
			$ldap_bind = @ldap_bind($ldap, $domain . $credentials['username'], $credentials['password']);
			
			if (!$ldap_bind) {
		        return false;
		    }

			return true;

		} catch (Exception $e) {
		
			// otherwise invalid
			return false;
		}
	}

	/**
	 * @param  array  $credentials - passes in username / password
	 * @return mixed
	 */
	public function retrieveByCredentials(array $credentials)
	{
		if($this->connectLdap($credentials)){
			return $user = new User($credentials);
		}
	}

	/**
	 * [validateCredentials description]
	 * @param  UserInterface $user        [description]
	 * @param  array         $credentials [description]
	 * @return boolean
	 */
	public function validateCredentials(UserInterface $user, array $credentials)
	{
		return $this->connectLdap($credentials);
	}

	public function retrieveByToken($identifier, $token){}
	public function updateRememberToken(UserInterface $user, $token){}
}