Complete step-by-step guide for integrating Didactum monitoring devices and sensors into isyVmon via SNMP – including host creation, check commands, service configuration, SNMP traps, and email alerting.

Note on the software: isyVmon is fully based on Nagios (monitoring engine) and Centreon (web interface). Therefore, all configuration steps described here also apply to pure Nagios and Centreon installations. Configuration files and menu paths are identical.

• Software: isyVmon (iT-CUBE SYSTEMS) – based on Nagios + Centreon
• Protocol: SNMP v1 / v2c / v3 via check_snmp plugin
• Devices: Didactum Monitoring System 100T / 300T / 500T / 550T
• Sensors: Temperature, leakage, humidity, door contact, smoke

isyVmon Server

• isyVmon installed as a virtual appliance or hardware appliance
• Web interface accessible (default: <Server-IP>/centreon)
• Nagios plugins installed (package nagios-plugins or monitoring-plugins)
• Package snmp and snmp-mibs-downloader installed
• UDP port 161 open outbound (SNMP polling)
• UDP port 162 open inbound (SNMP traps)

Didactum Device

• Monitoring System 100T / 300T / 500T or 550T
• SNMP enabled (v2c or v3)
• Network access to the isyVmon server
• MIB file available in the web interface

Architecture

[isyVmon / Nagios + Centreon] [Didactum Monitoring System]
IP: 192.168.1.10 IP: 192.168.1.50
Web: 192.168.1.10/centreon
--SNMP Polling UDP 161-->
<--SNMP Traps UDP 162---

Important directories on the isyVmon server

/usr/local/nagios/etc/ <-- Nagios configuration
/usr/local/nagios/etc/objects/ <-- Hosts, services, commands
/usr/lib/nagios/plugins/ <-- check_snmp and other plugins
/usr/share/snmp/mibs/ <-- MIB files
/var/log/nagios/nagios.log <-- Nagios logfile

Note: 

Paths may vary slightly depending on the isyVmon version and installation type. Alternative paths: /etc/nagios/, /etc/centreon/.

Step 1 – Open web interface

Open in browser: 192.168.1.50 (adjust IP of the Didactum device)

Step 2 – Open SNMP settings

System settings → SNMP

Step 3 – Enter the following values

SNMPv3 settings (optional, increased security)

Step 1 – Log in to the isyVmon server via SSH

ssh root@192.168.1.10

Step 2 – Install SNMP packages

sudo apt update
sudo apt install -y snmp snmp-mibs-downloader nagios-plugins

Check availability of check_snmp
ls /usr/lib/nagios/plugins/check_snmp
/usr/lib/nagios/plugins/check_snmp --help | head -10

Step 3 – Test SNMP connection to the Didactum device

# List all sensors
snmpwalk -v 2c -c didactum_isyvmon 192.168.1.50 .1.3.6.1.4.1.46501

Query temperature value directly (raw value ÷ 10 = degrees Celsius)
snmpget -v 2c -c didactum_isyvmon 192.168.1.50
.1.3.6.1.4.1.46501.5.1.1.7.101001

Test check_snmp plugin directly
/usr/lib/nagios/plugins/check_snmp
-H 192.168.1.50 -C didactum_isyvmon -P 2
-o .1.3.6.1.4.1.46501.5.1.1.7.101001
-w 280 -c 350 -l "Temperature"

Expected output: SNMP OK - 235

Step 1 – Download MIB from the Didactum web interface

System settings → SNMP → "Download MIB file" → didactum.mib

Step 2 – Install MIB on the server

sudo cp didactum.mib /usr/share/snmp/mibs/
echo "mibdirs /usr/share/snmp/mibs" | sudo tee -a /etc/snmp/snmp.conf
echo "mibs ALL" | sudo tee -a /etc/snmp/snmp.conf

Test using MIB name
snmpwalk -v 2c -c didactum_isyvmon -m ALL 192.168.1.50
DIDACTUM-MIB::sensorValue

isyVmon (Centreon) manages SNMP credentials as macros that are assigned to hosts and commands.

Navigation in the isyVmon/Centreon web interface

Configuration → Commands → Macros

Or directly in the host template (recommended):

Configuration → Hosts → Templates → "Didactum Template" edit
→ Macros → Add Macro

Additionally for SNMPv3:

Option A – Via the Centreon web interface (recommended)

Configuration → Hosts → Add

Click Save.

Option B – Directly as a Nagios configuration file

sudo nano /usr/local/nagios/etc/objects/didactum-hosts.cfg

# ================================================================

Didactum Monitoring System – Nagios host configuration
================================================================
define host {
host_name didactum-monitor-01
alias Didactum Monitoring System 01
address 192.168.1.50
check_command check-host-alive
max_check_attempts 3
check_interval 5
retry_interval 1
check_period 24x7
notification_interval 60
notification_period 24x7
notification_options d,u,r
contact_groups admins
hostgroups didactum-monitoring
# SNMP custom variables (for macros in commands)
_SNMPCOMMUNITY didactum_isyvmon
_SNMPVERSION 2
_SNMPPORT 161
}
define hostgroup {
hostgroup_name didactum-monitoring
alias Didactum Monitoring devices
members didactum-monitor-01
}

Option A – Via the Centreon web interface

Configuration → Commands → Checks → Add

Command: Didactum temperature

Click “Describe arguments” and describe the following arguments:

Command: Didactum leakage

Command: Didactum sensor status (general)

Option B – Directly as a Nagios configuration file

sudo nano /usr/local/nagios/etc/objects/didactum-commands.cfg

# ================================================================

Didactum SNMP check commands – Nagios configuration
================================================================
Temperature sensor with warning/critical thresholds
ARG1 = OID, ARG2 = Warning (×10), ARG3 = Critical (×10)
define command {
command_name check_didactum_temperature
command_line $USER1$/check_snmp -H $HOSTADDRESS$
-C $ARG4$ -P 2
-o $ARG1$ -w $ARG2$ -c $ARG3$
-l "Temperature" -u "0.1Degree"
}

Leakage sensor (0=OK, 1=CRITICAL)
define command {
command_name check_didactum_leakage
command_line $USER1$/check_snmp -H $HOSTADDRESS$
-C $ARG2$ -P 2
-o $ARG1$ -w 0:0 -c 1:1
-l "Leakage"
}

Sensor status (0=OK, 1=Alarm, 2=No signal)
define command {
command_name check_didactum_status
command_line $USER1$/check_snmp -H $HOSTADDRESS$
-C $ARG3$ -P 2
-o $ARG1$ -w 0:0 -c 1:2
-l "$ARG2$"
}

Humidity with thresholds in %
define command {
command_name check_didactum_humidity
command_line $USER1$/check_snmp -H $HOSTADDRESS$
-C $ARG4$ -P 2
-o $ARG1$ -w $ARG2$ -c $ARG3$
-l "Humidity" -u "%"
}

Door contact (0=closed=OK, 1=open=WARNING)
define command {
command_name check_didactum_door
command_line $USER1$/check_snmp -H $HOSTADDRESS$
-C $ARG2$ -P 2
-o $ARG1$ -w 1:1
-l "Door contact"
}

Option A – Via the Centreon web interface

Configuration → Services → Add

Service: Temperature sensor

Service: Leakage sensor

Service: Humidity

Service: Door contact

Service: Temperature sensor status

Option B – Directly as a Nagios configuration file

sudo nano /usr/local/nagios/etc/objects/didactum-services.cfg

# ================================================================

Didactum services – Nagios configuration
================================================================
--- Temperature sensor -------------------------------------------
define service {
host_name didactum-monitor-01
service_description Didactum Temperature Sensor 01
check_command check_didactum_temperature!.1.3.6.1.4.1.46501.5.1.1.7.101001!280!350!didactum_isyvmon
max_check_attempts 3
check_interval 5
retry_interval 1
check_period 24x7
notification_interval 60
notification_period 24x7
notification_options w,c,r
contact_groups admins
servicegroups didactum-sensors
}

--- Temperature sensor status -----------------------------------
define service {
host_name didactum-monitor-01
service_description Didactum Temp Status Sensor 01
check_command check_didactum_status!.1.3.6.1.4.1.46501.5.1.1.6.101001!Temp status!didactum_isyvmon
max_check_attempts 3
check_interval 5
retry_interval 1
check_period 24x7
notification_interval 60
notification_period 24x7
notification_options c,r
contact_groups admins
}

--- Leakage sensor ---------------------------------------------
define service {
host_name didactum-monitor-01
service_description Didactum Leakage Sensor 01
check_command check_didactum_leakage!.1.3.6.1.4.1.46501.5.1.1.7.107001!didactum_isyvmon
max_check_attempts 1
check_interval 2
retry_interval 1
check_period 24x7
notification_interval 30
notification_period 24x7
notification_options c,r
contact_groups admins
servicegroups didactum-sensors
}

--- Humidity ---------------------------------------------------
define service {
host_name didactum-monitor-01
service_description Didactum Humidity Sensor 01
check_command check_didactum_humidity!.1.3.6.1.4.1.46501.5.1.1.7.102001!80!90!didactum_isyvmon
max_check_attempts 3
check_interval 5
retry_interval 1
check_period 24x7
notification_interval 60
notification_period 24x7
notification_options w,c,r
contact_groups admins
servicegroups didactum-sensors
}

--- Door contact -----------------------------------------------
define service {
host_name didactum-monitor-01
service_description Didactum Door Contact 01
check_command check_didactum_door!.1.3.6.1.4.1.46501.5.1.1.7.104001!didactum_isyvmon
max_check_attempts 1
check_interval 1
retry_interval 1
check_period 24x7
notification_interval 30
notification_period 24x7
notification_options w,r
contact_groups admins
servicegroups didactum-sensors
}
define servicegroup {
servicegroup_name didactum-sensors
alias Didactum sensor services
}

Nagios/isyVmon does not receive traps directly. The path goes via snmptrapd → Nagios passive check.

Step 1 – Install and configure snmptrapd

sudo apt install snmptrapd -y
sudo nano /etc/snmp/snmptrapd.conf

authCommunity execute,log,net didactum_isyvmon
traphandle .1.3.6.1.4.1.46501 /etc/nagios/scripts/didactum-trap-handler.sh

Step 2 – Create trap handler script

sudo mkdir -p /etc/nagios/scripts
sudo nano /etc/nagios/scripts/didactum-trap-handler.sh

#!/bin/bash

================================================================
Didactum SNMP trap handler for Nagios/isyVmon
================================================================
NAGIOS_CMD="/var/run/nagios/nagios.cmd"
HOST="didactum-monitor-01"
SERVICE="Didactum SNMP Trap"
STATE=2 # CRITICAL
TIMESTAMP=$(date +%s)
MESSAGE="CRITICAL: Didactum SNMP trap received from $1 – $*"

Submit passive check result to Nagios
echo "[$TIMESTAMP] PROCESS_SERVICE_CHECK_RESULT;$HOST;$SERVICE;$STATE;$MESSAGE"
>> $NAGIOS_CMD

sudo chmod +x /etc/nagios/scripts/didactum-trap-handler.sh

Step 3 – Create passive service in Nagios/Centreon

sudo nano /usr/local/nagios/etc/objects/didactum-trap-service.cfg

define service {
host_name didactum-monitor-01
service_description Didactum SNMP Trap
check_command check_dummy!0!"Waiting for SNMP traps..."
active_checks_enabled 0
passive_checks_enabled 1
max_check_attempts 1
check_interval 10
check_period 24x7
notification_interval 30
notification_period 24x7
notification_options c,r
contact_groups admins
}

Step 4 – Start snmptrapd

sudo systemctl enable snmptrapd
sudo systemctl start snmptrapd

All Didactum OIDs begin with .1.3.6.1.4.1.46501 (older firmware) or .1.3.6.1.4.1.39052 (newer models). The sensor ID is appended at the end.

OID fields per sensor

Sensor types with OIDs

Determine sensor ID: 

In the Didactum web interface under System tree → select sensor → details. This ID is appended to the end of the OID.

Temperature thresholds in check_snmp: 

check_snmp works with the raw value. Thresholds must be entered × 10. 28 °C = input value 280, 35 °C = input value 350.

MIB prefix per model: 

Older devices use .1.3.6.1.4.1.46501, newer models may use .1.3.6.1.4.1.39052. Refer to the exact OIDs in the MIB file of your device.

Step 1 – Create contact

In the Centreon/isyVmon web interface:

Configuration → Users → Contacts → Add

Step 2 – Create contact group

Configuration → Users → Contact Groups → Add
Group Name: admins
Members: admin

Step 3 – Ensure mail delivery on the server

sudo apt install postfix mailutils -y

Select configuration type: "Internet Site"
Test:
echo "Test mail isyVmon" | mail -s "Test" admin@yourdomain.com

Step 4 – Check Nagios notification commands

# Default commands are already present in the Nagios configuration:
grep -A5 "notify-service-by-email" /usr/local/nagios/etc/objects/commands.cfg

The default Nagios notification commands automatically send emails when a service changes to WARNING, CRITICAL, or UNKNOWN state and a contact is assigned.

All changes made via the Centreon/isyVmon web interface must be exported so that Nagios applies them.

Option A – Via the Centreon web interface (recommended)

Configuration → Pollers → Central → Export configuration

Enable the following options:

• Generate configuration files: Yes
• Run monitoring engine debug (-v): Yes (for initial test)
• Move export files: Yes
• Restart monitoring engine: Yes
• Method: Restart

Click Export. Centreon generates the Nagios configuration files and restarts Nagios.

Option B – Directly via command line

# Check configuration for syntax errors
sudo nagios -v /usr/local/nagios/etc/nagios.cfg

Reload Nagios (no full restart required)
sudo systemctl reload nagios

If errors occur: full restart
sudo systemctl restart nagios

Check status
sudo systemctl status nagios

Option C – Include directly in isyVmon configuration file

sudo nano /usr/local/nagios/etc/nagios.cfg

Add the following lines (if not present):

cfg_file=/usr/local/nagios/etc/objects/didactum-hosts.cfg
cfg_file=/usr/local/nagios/etc/objects/didactum-commands.cfg
cfg_file=/usr/local/nagios/etc/objects/didactum-services.cfg
cfg_file=/usr/local/nagios/etc/objects/didactum-trap-service.cfg

Test check_snmp directly

# Temperature value (expected: SNMP OK - 235)
/usr/lib/nagios/plugins/check_snmp
-H 192.168.1.50 -C didactum_isyvmon -P 2
-o .1.3.6.1.4.1.46501.5.1.1.7.101001
-w 280 -c 350 -l "Temperature"

Leakage status (expected: SNMP OK - 0)
/usr/lib/nagios/plugins/check_snmp
-H 192.168.1.50 -C didactum_isyvmon -P 2
-o .1.3.6.1.4.1.46501.5.1.1.7.107001
-w 0:0 -c 1:1 -l "Leakage"

Validate Nagios configuration

sudo nagios -v /usr/local/nagios/etc/nagios.cfg

Expected output: "Things look okay - No serious problems..."

Check service status in the Centreon/isyVmon web interface

Monitoring → Services → By Host
→ Host: didactum-monitor-01
→ View status of the Didactum services

Error messages and solutions

View Nagios logs

sudo tail -f /var/log/nagios/nagios.log
sudo tail -f /var/log/nagios/host-perfdata

Didactum device

• SNMP enabled (v2c or v3)
• Community string set (not “public”)
• Trap receiver IP set to isyVmon server
• Trap port 162 configured
• MIB file downloaded
• snmpwalk test from the isyVmon server successful

isyVmon / Nagios server

• Packages snmp, snmp-mibs-downloader, nagios-plugins installed
• MIB file stored under /usr/share/snmp/mibs/
• check_snmp successfully tested directly on the command line
• Firewall: UDP 161 outbound, UDP 162 inbound open

Centreon / isyVmon web interface

• SNMP community stored as host macro
• Host “didactum-monitor-01” created (IP, community, template)
• Check commands defined for all sensor types
• Services created for temperature, leakage, humidity, door contact
• Contact with email address and contact group created
• Contact group assigned to the services
• Configuration exported (Configuration → Pollers → Export)

Tests & validation

• nagios -v: configuration error-free
• Monitoring view: services show current status
• Temperature thresholds: raw value × 10 entered correctly
• Test alert triggered and email received
• SNMP trap reception tested (optional)