Use this function for debug snmp-connection.<?phperror_reporting(8191);date_default_timezone_set('Europe/Moscow');ini_set('display_errors',1);snmp_test_connection('12.34.56.78', 'guest', 'guest')function snmp_test_connection($ip, $user, $pass){ $a = array('noAuthNoPriv','authNoPriv','authPriv'); $b = array('MD5','SHA'); $c = array('DES','AES'); $branch = '.1.3.6.1.2.1.1.3'; foreach($a as $aPriv) foreach($b as $bProt) foreach($c as $cPrivProt){ echo 'time = '.date('Y-m-d H:i:s').'<br/>'; echo '<b>sec_level=</b>'.$aPriv.'<br/><b>auth_protocol=</b>'.$bProt.'<br/><b>priv_protocol=</b>'.$cPrivProt.'<br/>Request = '; var_dump( snmp3_real_walk($ip, $user, $aPriv, $bProt, $pass, $cPrivProt, $pass, $branch) ); }}?>