Out of the box, PRTG Network Monitor offer various sensors defined within the various provided libraries. However, sometimes these included libraries do not suffice and it is necessary to access devices by directly providing Object Identifiers (OIDs).

However, OIDs are generally not openly available in the documentation provided by hardware manufacturers. The manufacturers offer so-called MIB files which contain the information to create OIDs.

Using Paessler's MIB Importer you can import and convert MIB files, but sometimes the MIB files can't be loaded (the standards for MIB files are often interpreted in various ways which results in incompatible files).

If you can't convert your MIB file there is one other option to discern these OIDs to be used by PRTG.

Using GetIf to discern OIDs

GetIf is a handy little tool that can be used to ascertain and discern OIDs which, in turn, can be used to access custom sensor information. Setting up GetIf is quick and simple. Simply download the data files, execute the Setup routine and GetIf will automatically install itself on your machine. You can download the file from:

http://www.wtcs.org/snmp4tpc/getif.htm,

Then, start the program from the GetIf program group (Start | Programs | GetIf). You will need to enter the IP address for the server upon which you would like to look up the OIDs. You will also need to define various SNMP parameters (such as the Read / Write community strings).

In order to then access the OIDs, click on the "MBrowser" tab. If all was set up properly, you will notice boxes which, upon clicking on them, will open into a tree structure. At the bottom left, you will notice a number - this number is the OID. The further you go in the tree structure, the longer the number should get, as the individual nodes are being added to the OID value.

Find the device you are wanting to use in PRTG and use the OID value presented by GetIf in order to set up a custom sensor - in this manner you can configure your own devices which might not be accessible directly from the provided libraries.

Note: Please note that this works only if the MIB files (the description files for OID trees) for your device are already provided with GetIF. Please refer to the documentation to use your own MIB files.

Setting up "SNMP Custom" sensors in PRTG

Once you have the necessary OIDs, you can go and use these values to set up custom sensors in PRTG. Setting up custom sensors in PRTG is easy, once you have the necessary OID values.

First, select to add a new sensor by using the "Add Sensor" function of PRTG. Follow the sensor configuration instructions and, when asked which type of sensor you would like to set up, select "SNMP Custom" from the SNMP sensor type option. On the next screen configure the sensor accordingly, providing the OID in the "OID value" field.

Select to continue and, if everything was defined properly the sensor should automatically have been added to the respective device and should generate a graph and provide the required values.

Keep in mind that many sensor values are already included in the accompanying Paessler libraries - not every sensor that you configure requires you to set up a custom sensor and input a respective OID.