function authAD($username, $password, $Domain, $ldap_server) { 
	if ($password == ""){ // POZOR: pouziti prazdneho hesla by proslo
		return(false);
	}
	if (function_exists('ldap_connect')) {
		$auth_user = $username."@".$Domain;
		if($connect = ldap_connect($ldap_server)){
			ldap_set_option($ds, LDAP_OPT_PROTOCOL_VERSION, 3);
			ldap_set_option($ds, LDAP_OPT_REFERRALS, 0);
			//ldap_set_option(NULL, LDAP_OPT_DEBUG_LEVEL, 7); // pise do error logu apache prubeh
			if(@ldap_bind($connect, $auth_user, $password)) {
				ldap_close($connect);
				return(true);
			}
		}
		ldap_close($connect);
		return(false);
	}
	else {
		Die ("extension php_ldap neni dostupne");
	}
}

if(authAD("username", "password", "DOMAIN", "ldap://ip_adress")) {
	echo "login OK.";
	// .... Vas kod
}
else {
	 echo "login ERROR";
	// .... Vas kod
}