Set up SNMP MIB monitoring

Monitor sensor health through the Simple Network Management Protocol (SNMP), as the sensor responds to SNMP requests sent by an authorized monitoring server, and the SNMP monitor polls sensor OIDs periodically (up to 50 times a second).

Supported SNMP versions are SNMP version 2 and version 3. The SNMP protocol utilizes UDP as its transport protocol with port 161.


Prerequisites for AES and 3-DES Encryption Support for SNMP Version 3

  • The network management station (NMS) must support Simple Network Management Protocol (SNMP) Version 3 to be able to use this feature.

  • It's important to understand the SNMP architecture and the terminology of the architecture to understand the security model used and how the security model interacts with the other subsystems in the architecture.

  • Before you begin configuring SNMP monitoring, you need to open the port UDP 161 in the firewall.

Set up SNMP monitoring

Set up SNMP monitoring through the OT sensor console.

You can also download the log that contains all the SNMP queries that the sensor receives, including the connection data and raw data, from the same SNMP MIB monitoring configuration pane.

To set up SNMP monitoring:

  1. Sign in to your OT sensor as an Admin user.

  2. Select System Settings on the left and then, under Sensor Management, select SNMP MIB Monitoring.

  3. Select + Add host and enter the IP address of the server that performs the system health monitoring. You can add multiple servers.

    For example:

    Screenshot of the SNMP MIB monitoring configuration page.

  4. In the Authentication section, select the SNMP version:

    • If you select V2, type a string in SNMP v2 Community String.

      You can enter up to 32 characters, and include any combination of alphanumeric characters with no spaces.

    • If you select V3, specify the following parameters:

      Parameter Description
      Username Enter a unique username.

      The SNMP username can contain up to 32 characters and include any combination of alphanumeric characters with no spaces.

      The username for the SNMP v3 authentication must be configured on the system and on the SNMP server.
      Password Enter a case-sensitive authentication password.

      The authentication password can contain 8 to 12 characters and include any combination of alphanumeric characters.

      The password for the SNMP v3 authentication must be configured on the system and on the SNMP server.
      Auth Type Select MD5 or SHA-1.
      Encryption Select one of the following:
      - DES (56-bit key size): RFC3414 User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3).
      - AES (AES 128 bits supported): RFC3826 The Advanced Encryption Standard (AES) Cipher Algorithm in the SNMP User-based Security Model.
      Secret Key The key must contain exactly eight characters and include any combination of alphanumeric characters.
  5. When you're done adding servers, select Save.

Download the SNMP MIB file

To download the SNMP MIB file from Defender for IoT in the Azure portal:

  1. Sign in to the Azure portal.
  2. Select Sites and sensors > More actions > Download SNMP MIB file.

All files downloaded from the Azure portal are signed by root of trust so that your machines use signed assets only.

Sensor OIDs

Use the following table for reference regarding sensor object identifier values (OIDs):

Management console and sensor OID Format Description
Appliance name STRING Appliance name for the on-premises management console
Vendor STRING Microsoft Support (
Platform STRING Sensor or on-premises management console
Serial number STRING String that the license uses
Software version STRING Xsense full-version string and management full-version string
CPU usage GAUGE32 Indication for zero to 100
CPU temperature STRING Celsius indication for zero to 100 based on Linux input.

Any machine that has no actual physical temperature sensor (for example VMs) will return "No sensors found"
Memory usage GAUGE32 Indication for zero to 100
Disk Usage GAUGE32 Indication for zero to 100
Service Status STRING Online or offline if one of the four crucial components is down
Locally/cloud connected STRING Activation mode of this appliance: Cloud Connected / Locally Connected
License status STRING Activation period of this appliance: Active / Expiration Date / Expired

Note that:

  • Non-existing keys respond with null, HTTP 200.
  • Hardware-related MIBs (CPU usage, CPU temperature, memory usage, disk usage) should be tested on all architectures and physical sensors. CPU temperature on virtual machines is expected to be not applicable.

Next steps

For more information, see Export troubleshooting logs