I would like to add an SNMP Custom sensor in PRTG, for example for a particular SNMP counter. But how do I find out the precise OID I need to use?
This article applies to PRTG Network Monitor 16 or later
OIDs for SNMP Custom Sensors
OIDs are unique addresses of monitoring objects and are the key to a wealth of information about your network that you can monitor via SNMP. How do you find out what OIDs you need?
1. Check OID Resources
PRTG Network Monitor already offers a lot of SNMP Sensors out of the box. This means that various SNMP libraries and most used MIBs are already provided in PRTG.
Check 1: To check if your device is already covered by PRTG, just start an auto-discovery. PRTG will then create all available sensors and channels automatically.
If your device type was not covered or if you use SNMP Custom sensors to monitor specific devices, you need to provide one or more specific OIDs to directly access the monitoring objects on these devices.
In most cases, single OIDs are not explicitly made available in the documentation provided by hardware manufacturers.
However, the manufacturers (should) provide the MIB files that contain the necessary device information and allow you to retrieve the OIDs.
Check 2: You can either contact your device manufacturer or see this article on where to find MIBs on the web.
2.A Import MIB Files to PRTG
Once you got the MIB files you need you can import them into PRTG using the Paessler MIB Importer.
It converts the MIB files into oidlib files, a PRTG format for MIB files. This makes them best readable by PRTG and enhances functionality for monitoring.
Just follow the MIB Importer instructions.
The standards for creating MIB files are often interpreted in various ways by developers all over the world. Therefore, your import may result in incompatible files.
If MIB files could not be converted successfully or could not be loaded correctly, you can try the following option to find out which OIDs you need for your SNMP Custom sensors.
2.B Debug: Use the Paessler SNMP Tester
With the SNMP Tester you can run simple SNMP requests against a device in your network. This test program is based on the SNMP technologies built into PRTG Network Monitor.
It aims to
- enable SNMP debugging.
- perform SNMP walks. You can use the Walk option of the SNMP Tester to check OIDs, and to discover OIDs that you can use to access custom monitoring objects.
These are the steps to go:
- Download the SNMP Tester and unzip all files on your machine, preferably the computer on which you run a PRTG probe (local or remote).
- Start the SNMP Tester by running snmptest.exe.
- Enter the IP address or DNS name for the server on which you would like to look up the OIDs. Define also the SNMP parameters asked for, like port, SNMP version, and community string, depending on the SNMP settings on your target device.
- Check if you can access the target device via SNMP.
- In section Select Request Type, choose Read Device Uptime.
- In section Run Test, click Start.
- If this first test was successful, you are ready to use the other SNMP Tester request types to discern all available OIDs on your target system.
- In section Select Request Type, choose Walk.
- Enter 1.3.6 into the Walk field. This is usually the part that OIDs start with.
- Click Start.
- After some time, depending on the amount of SNMP information provided by the target device, the SNMP Tester will list all OIDs it could find with their current value and value type. The type is important to add the correct SNMP Custom sensor type to PRTG to request a specific OID.
3. Set Up Your SNMP Custom Sensors in PRTG
Having saved the OIDs you need, you can now set up your individual SNMP Custom sensor.
- Go to a device in your device tree and open the Add Sensor dialog.
- Choose the SNMP Custom sensor you want and follow the instructions.
- Have your OID ready to enter it when PRTG asks you to do so.
- Have fun Monitoring via SNMP!
Note: Before you spend your time searching for MIBs and and custom OIDs, check PRTG's built-in SNMP libraries first (see Check 1 above)!
One further option is to use SNMPUtil to walk / get an OID root / branch via the command console.
The necessary syntax would be:
SNMPUTIL [get|getnext|walk] [IP address] [community] [OID]
SNMPUTIL walk 10.0.0.1 public 220.127.116.11
SNMPUtil can be downloaded from:
Further information on SNMPUtil is available under: