Is there a device on your network that you want to learn more about or monitor? Being able to look up the device’s Object Identifiers, or OIDs, is the key to gleaning the information you’re after.
What’s an OID?
An OID is a unique identifier assigned by the SNMP protocol to the various components of individual devices. The OID is based in part on the Management Information Base, or MIB, to which the device belongs.
Each OID contains information about a particular aspect of a device, which can be helpful when troubleshooting a network or studying the network topography. For example, you can grab an OID that tells you about the temperature of a device. Another OID might tell you about uptime, while a third OID reveals details about fan speed.
OID data can also be used to determine the vendor that manufactured the device, just as MAC addresses on networking hardware can usually be traced to specific vendors. Manufacturer information can often be difficult to find in any other way so the OID comes in quite handy in that regard. Once you know the manufacture, you can look up documentation if needed.
How to look up OIDs
Some network systems, like Auvik, already contain the OIDs for a huge variety of devices. But sometimes you’ll want to look up a custom OID so you can add it to your monitoring by hand. That’s when you’ll need to use an OID lookup service.
A number of websites offer OID lookup services. They vary in quality, completeness, and usability. In my book, the OID Repository is one of the best. Downloadable OID lookup tools, such as iReasoning, are also available, but I tend to prefer web-based solutions because they’re convenient and cross-platform.
If you don’t have any luck finding OID information for a device in one of the big, generic databases, try looking in a vendor-specific database. For example, you can browse Cisco OID data here. Vendor databases sometimes provide more information about OIDs than you can find in a general-purpose OID database.
For finding manufacturer information, I also like Wireshark’s OUI Lookup Tool. As the name implies, this tool lets you look up OUIs, or Organization Unique Identifiers—the part of an OID that tells you which vendor is associated with the device in question. It doesn’t provide information about the entire OID, however.
Strings and numbers
When you’re finding the OID for the device you want to look up, keep in mind that OIDs can be represented either as numbers or as strings—just as a device’s location on the network could be represented by an IP address or a hostname, which are interchangeable as long as both are part of your known DNS records.
Despite the interchangeability of strings and numbers from the SNMP protocol’s perspective, many OID databases require you to enter OIDs in numerical form, so you may need to translate from strings to numbers using a tool like snmptranslate before entering the OID into the database.
OIDs and Auvik
Auvik lets you add and edit any specific OIDs you want to monitor. Once you have the OID in number format, follow the instructions in How do I manage OID monitor settings? to add it to your Auvik instance.