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
Finding OIDs for SNMP Custom Sensors
PRTG Network Monitor already offers a lot of SNMP Sensors out of the box. This means that various SNMP libraries and MIBs are already provided in PRTG.
If you use SNMP Custom sensors to monitor specific devices, you need to provide one or more specific OIDs to directly access these devices.
However, OIDs often are not directly available in the documentation provided by hardware manufacturers. The manufacturers offer MIB files that contain the necessary information to create OIDs.
Importing MIB Files to PRTG
You can import these specific MIBs in PRTG using the Paessler MIB Importer. It converts the MIB files into OIDLIB files and makes them best readable by PRTG. Just follow the MIB Importer instructions.
The standards for MIB files are often interpreted in various ways which results in incompatible files. So, 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.
Using the Paessler SNMP Tester to Discern OIDs
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.
The idea of this program is to have a tool that enables you to debug SNMP activities. You can also use the Walk option of the SNMP Tester to check and discern OIDs which, in turn, you can to access custom sensor information.
- 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 the test was successful, you are ready to discern all available OIDs.
- In section Select Request Type, choose Walk.
- Enter 1.3.6 into the Walk field. This is usually the part 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.
Setting up 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 OIDs ready to enter it when PRTG asks you to do so.
- Have fun Monitoring via SNMP!
Note: Keep in mind that many sensor values based on specific OIDs are already included in the PRTG SNMP libraries. Not every custom sensor requires looking for a specific OID first.
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 18.104.22.168
SNMPUtil can be downloaded from:
Further information on SNMPUtil is available under: