At first the command definition has to be done in the Nagios configuration by the following (i.e.):

define command {
  command_name  check_ironport_snmp
  command_line  $PATH$/check_ironport.pl -H $HOSTADDRESS$ -C $SNMP_COMMUNITY$ -x $ARG1$
    -w $ARG2$ -c $ARG3$
}
define command {
  command_name  check_ironport_snmp_licence
  command_line  $PATH$/check_ironport.pl -H $HOSTADDRESS$ -C $SNMP_COMMUNITY$ -w $ARG2$
    -c $ARG3$ -x keySecondsUntilExpire -l $ARG1$
}
define command {
  command_name  check_ironport_snmpv3
  command_line  $PATH$/check_ironport.pl -H $HOSTADDRESS$ -s 3 -C $SNMP_PASSWORD$ -x $ARG1$
    -w $ARG2$ -c $ARG3$
}

Afterwards a service can be configured in the Nagios configuration by setting the 'check_command' for example to the following:

check_command  check_ironport_snmp!c-workQueueMessages!200!250

This command would check the amount of messages in the work-queue of a Ironport Mail Security Appliance. A WARNING will be evaluated if this amount is between 200 and 250. If the value is even above 250, status will be set to CRITICAL.

Defining a check command for the licence keys is done by:

check_command  check_ironport_snmp_licence!'Cisco IronPort Web Usage Controls,Sophos,
  IronPort Web Proxy & DVS(TM) Engine,IronPort Web Reputation Filters'!28!7

This check command tells the PlugIn to check for the 4 different feature keys and creates a WARNING if the key is expiring within 28 days or creates a CRITICAL if the key is expiring within 7 days.

perl check_ironport.pl -h
check_ironport.pl - SNMP Ironport monitor PlugIn for Nagios in version 1.0
Copyright (C) 2011-2013 Stefan Heumader <stefan@heumader.at>

check_ironport.pl usage: check_ironport.pl [-v] -H <host> [-s <snmpversion>]
-C <SNMPv12 Community|SNMPv3 password> [-p <port>] -w <warning_level>
-c <critical_level> [-t <timeout>] [-V] -x <category>
[-l <comma seperated licence items>]

-h, --help
	print this help message
-V, --version
	prints version number of Nagios PlugIn
-v, --verbose
	print extra debug informations
-H, --hostname=HOST
	name or IP address of host to check
-C, --community=COMMUNITY NAME
	SNMPv2 community name for the host's SNMP agent
	SNMPv3 user password
-P, --port=PORT
	SNMP port (default 161)
-s, --snmpversion=VERSION
	SNMP version (default 2)
-w, --warn=INTEGER
	warning threshold (necessary)
-c, --crit=INTEGER
	critical threshold (necessary)
-x, --category=STRING
	defines which information should be read (...)
-l, --licence=STRING
	comma septerated list of licence items

The actual version supports the following services to evaluate:

• perCentMemoryUtilization memory utilization in percent, define warning and critical threshold
• perCentCPUUtilization CPU utilization in percent, define warning and critical threshold
• memoryAvailabilityStatus returns the state predefined by Ironport
• openFilesOrSockets amount of open files or sockets, define warning and critical threshold
• powerSupplyRedundancy returns the state predefined by Ironport
• powerSupplyStatus returns the state predefined by Ironport, NoAC will be a WARNING
• raidStatus returns the state predefined by Ironport, rebuilding the RAID will be WARNING
• raidLastError last error message of a RAID device, service will go CRITICAL if message differs from 'No Errors'
• degreesCelsius degrees in Celsius, define warning and critical threshold
• keySecondsUntilExpire amount of days to expiration of a feature key, define warning and critical threshold days, you need also to define a list of feature keys, which should be checked
• c-workQueueMessages the amount of messages in the work-queue, define warning and critical threshold
• c-queueAvailabilityStatus returns the state predefined by Ironport
• c-resourceConservationReason returns the state predefined by Ironport
• c-perCentQueueUtilization queue utilization in percent, define warning and critical threshold
• c-oldestMessageAge seconds of oldest message in queue, define warning and critical threshold
• c-mailTransferThreads amount of mail transfer threads, define warning and critical threshold