The NiTO agent performs SNMP checks against “peer” devices (devices accessible to the agent within your network), by scanning for a range of known OIDs/MIBs. Most SNMP capable switches/routers, for example, present bandwidth information through the same set of common OIDs.

How you enable SNMP on the hardware itself can vary greatly from one vendor, or make/model, to the next. In addition to the common OIDs, most SNMP devices also have a range of proprietary OIDs/MIBs. Sometimes, even the firmware on these devices contain bugs and don’t present accurate data.

While we cannot cover the all of the implantation details for every type of device, we do make the process as simple as possible. There are a few basic principles to keep in mind when configuring SNMP devices, from the device itself to NiTO.

  • SNMP isn’t usually enabled by default on the machine itself. You must enable SNMP via the proprietary interface or configuration files on the machine itself.
  • The ‘community’ must be configured on the SNMP device with access to the entire SNMP/OID tree. NiTO does not require SET (write) access; GET (read) access is sufficient for monitoring with NiTO.
  • By default, NiTO uses version 2c of the SNMP protocol. Ensure that the SNMP device itself and NiTO are configured with the same protocol (in NiTO, this can be defined in the SNMP configuration popover, under ‘Advanced Options’).
  • The machine performing the check must have the NiTO agent installed on it, with the SNMP device as a “peer” check of that agent. The agent machine must be able to establish a network route to the SNMP machine to be monitored.

SNMP Utils

The NiTO agent installs the net-snmp-utils package by default on Linux. On Windows, snmpget, snmpwalk, and snmpbulkwalk are included and can be found under C:\Program Files (x86\Nito\Bin (assuming default installation path). You can use these utilities to directly troubleshoot communication problems between the agent machine and the SNMP machine. If an error occurs when you run these commands directly, it’s a strong indicator that NiTO will not be able to communicate with the SNMP machine either.

To test whether the agent’s machine can access the required range of OIDs on the SNMP machine, run the following command in a terminal on the agent machine (within the C:\Program Files (x86\Nito\Bin directory, if Windows) (replace [community] [address] appropriately):

snmpwalk -v 2c -c [community] [address] 1.3.6.1.2.1.1

NOTE

An SNMP time-out error doesn’t always indicate a routing problem. A time-out may occur due to an incorrect community string, or if the community string doesn’t have access to the request OIDs/MIBs (the SNMP machine simply won’t respond to unauthorized requests).