With this command it's works great. ./check_snmp -P 3 -U testuser -L authPriv -a SHA -A passwd -x DES -X passwd 10.10.10.254 -o SNMPv2-MIB::sysDescr.0 Example : SNMP OK - Cisco NX-OS(tm) n5000, Software (n5000-uk9), Version 5.0(3)N2(1), RELEASE SOFTWARE Copyright (c) 2002-2011 by Cisco Systems, Inc....