EDIT: All firmware and models are compatible, that is why nothing is posted about it. Okay, so there will be a lot here, so please bare with me. I've been working on this now for a few hours (reading manuals and such) so I'm not just coming here right out of the blue. I am working on a PRE-EXISTING Nagios server where there are several other existing plugins and checks running and working. Now I want to add another server there to check so I made the following modifications: First and foremost, I added a file to /usr/local/nagios/libexec named: check_equallogic.sh. The permissions are 755, the same as all others. I have chowned to nagios:nagios and in the listing it shows the Owner as Nagios. I then added a command to the commands.cfg file in \usr\local\nagios\etc\objects that shows the following: # 'check_equallogic' command definition define command{ command_name check_equallogic command_line $USER1$/check_equallogic -H $HOSTADDRESS$ -C $ARG1$ -t $ARG2$ $ARG3$ } Following this, I created a file named equallogic.cfg in the objects directory and it contains (more or less): define host{ use linux-server ; Inherit default values from a template host_name 172.16.50.11 ; The name we're giving to this device alias EqualLogic ; A longer name associated with the device address 172.16.50.11 ; IP address of the device contact_groups admins } Check Equallogic Information define service{ use generic-service host_name 172.16.50.11 service_description General Information check_command check_equallogic!public!info } After ensuring that permissions are okay for all files, I restart the nagios service, no errors. When I go into the WebGUI, I get the following errors AFTER the check runs: (Return code of 127 is out of bounds - plugin may be missing) Extra, probably unrelated problem Furthermore, when I log into the EquilLogic server, under Audit logs I get the following error: Level: AUDIT Time: 26/05/2014 3:59:13 PM Member: ps4100-1 Subsystem: agent Event ID: 22.7.1 SNMP packet validation failed, request received from 172.16.10.11 An snmpwalk receives a timeout, whereas others succeed. I will work on importing the MIBs tomorrow. The reason why I am mentioning it is because I want to make sure that it is only a MIB issue for the SNMP. If it is, then ignore this area. I am entirely unsure of what to do here.