How are SNMP Devices discovered? (NETIQKB43553)

The SNMP Generic Toolkit is a proxy based module in which an AppManager Agent with the SNMP Module installed (SNMP Proxy Agent) handles all monitoring activity for a set of discovered SNMP Devices. As released, the SNMP Generic Toolkit Module supports up to 50 SNMP Devices per SNMP Proxy Agent.

Even though this module is proxy based, SNMP Discovery still operates in the same way as any other AppManager Module. When devices are discovered, they will appear in the AppManager TreeView under the hostname of the SNMP Proxy Agent in the following form:

SNMP Proxy Agent: <Hostname>

• Devices
• <Device 1>
• <Device 2>
• <Device 3>
• ?

Before Discovery can be performed, SNMP community strings must be supplied for the devices to be discovered. These can be configured using the AppManager Security Manager component. Instructions are in the Working Smarter Guide PDF supplied with the module (Monitoring SNMP with AppManager). Alternately, a single community string can be entered directly into the Discovery_Snmp script. However, if all the devices to be discovered are not using this one community string, it will not be possible to discover all of the devices. If all else fails, ?public? will be used as a default community string.

NOTE: If it is intended to use the SyncSet script on an SNMP Device, then a read/write community string must be configured rather than a read/only community string.

NOTE: If the NetworkDevices module is installed on the same AppManager Agent as the SNMP Module, the SNMP Module will make use of the NetworkDevices community strings if all other sources fail. This negates the need to configure the same community strings for both modules.

Discovery_Snmp Script Parameters

SNMP Discovery is not automated. All devices to be discovered must be supplied by hostname or IP address in the Discovery_Snmp script parameters. This can be done in any or all of three ways:

1. Supply individual hostnames and IP addresses.
2. Supply IP Address Ranges up to 255 addresses wide (e.g. 10.41.1.1-10.41.1.255).
3. Supply the path to a file containing a list of individual hostnames and IP addresses. The file must be locally accessible to the SNMP Proxy Agent performing Discovery.

SNMP Discovery Outcomes

There are three possible outcomes for SNMP Discovery:

1. Success ? All devices were discovered and there were no errors.
2. Partial ? Some devices were discovered, but errors were encountered for other devices.
3. Failure ? No devices were discovered; errors were encountered for every device.

SNMP Discovery Errors

There are three categories of errors that can occur during discovery:

1. SNMP Timeouts ? The device did not respond.
2. Bad Hostnames ? The module was unable to resolve the hostname to an IP Address.
3. SNMP Response Errors ? The SNMP Device sent back an error to an SNMP Request.

For Partial Discovery or Failed Discovery, the detailed message of the Discovery Event will list how many of each type of error occurred, along with the associated host names or IP Addresses.