function send() { $response = new dhcpPacket(); $response->setData('op', dhcpPacket::int2hex(1)); $response->setData('xid', '12345678'); // $response->setData('chaddr', ); $response->setData('htype', '00'); $response->setData('hlen', '00'); $response->setData('ciaddr', dhcpPacket::ip2hex(array(129, 21, 50, 223))); $response->setData('message_type', 'DHCPLEASEQUERY'); $responseData = $response->build(); $error = socket_sendto($this->socket, $responseData, strlen($responseData), 0, '129.21.49.137', 67); print_r($error); if ($error === FALSE) { print "Send failed for address"; } }