Use the Discovery_Snmp Knowledge Script to discover SNMP-enabled devices running on a network. The AppManager agent on which the SNMP Toolkit is installed acts as a proxy for discovering SNMP devices. This AppManager agent is referred to as the SNMP proxy agent computer.
By default, this script runs once for each computer.
In a successful discovery, the following details are discovered:
|
Object |
Discovered Details |
|---|---|
|
SNMP Proxy object |
Agent Address – The hostname or IP address of the SNMP proxy agent computer. |
|
SNMP Device object |
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Devices can only be discovered by providing a device list of hostnames, IP addresses, or IP address ranges for the corresponding Discovery Knowledge Script parameters. There is no automatic discovery capability. The Discovery_Snmp script iteratively attempts to contact and retrieve the System MIB from each supplied hostname or IP address.
Because many SNMP devices (typically routers) have multiple IP addresses, some devices may be discovered multiple times. In these cases, the Discovery script automatically detects and removes the duplicates from the list of discovered devices. Any duplicates are shown in the AppManager TreeView pane under the IP address or hostname under which they were first discovered.
During discovery, various errors may occur with the supplied list of SNMP devices. Most commonly, these will be SNMP timeouts from devices failing to respond because they are down, because they are not running an SNMP agent, or because the community string supplied for the device is incorrect. Other common errors can be due to bad hostnames or SNMP Response errors.
Discovery can take anywhere from a few seconds to several minutes or hours. The time taken largely depends on how many SNMP timeouts occur. For example, if this script is configured with an SNMP timeout value of 5 seconds and 3 SNMP retries, it takes 20 seconds to determine that the device is not responding.
The time taken for discovery to finish can be controlled by limiting the use of IP address ranges, which are likely to contain many addresses that are not used or that do not correspond to SNMP devices, and to keep the SNMP timeout/retry values as small as is practical for the local network environment.
Set the following parameters as needed:
|
Parameter |
How to Set It |
|---|---|
|
Discovery Parameters |
|
|
List of SNMP devices |
Supply a list of SNMP device hostnames or IP addresses for the devices you want to monitor. An attempt is made to discover each device listed. The default is localhost. |
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Address ranges of SNMP devices |
Instead of listing each IP address individually in List of SNMP devices, you can provide a list of IP address ranges. Each range must be in the format “A.B.C.D-W.X.Y.Z”. For example, enter “10.1.1.0-10.1.1.254”. Each address range may be no longer than 255 addresses, although they can span subnets. For example, “10.1.1.250-10.1.2.30” spans a subnet. |
|
Full path to file with list of SNMP devices |
Instead of listing each IP address or range of addresses, you can supply the full path to a file containing a list of individual IP addresses or hostnames. The file path supplied must be accessible from the SNMP proxy agent computer, not the AppManager Operator Console or repository computer. Device names can be separated by commas, blank characters or new lines. |
|
Maximum number of devices to discover |
Specify the maximum number of devices to be discovered. Discovery stops when this limit is reached, even if not all IP addresses and hostnames have been attempted. The default and maximum allowed value is 250. |
|
SNMP port number |
Specify the UDP port number on the remote SNMP device to which you want to send SNMP requests. The default is 161. |
|
SNMP retries |
Specify the number of retries to attempt if a timeout occurs on an SNMP request. The default is 1 retry. |
|
SNMP timeout |
Specify the number of seconds to wait for a response before timing out an SNMP request. The default is 3 seconds. |
|
Trap Receiver Discovery |
|
|
Discover Trap Receiver? |
Set to Yes to discover NetIQ SNMP Trap Receiver. The default is Yes. For more information, see Section 2.10, Working with NetIQ SNMP Trap Receiver. |
|
Trap Receiver IP address |
Specify the IP address of the computer on which Trap Receiver is installed. The default is localhost. |
|
Trap Receiver TCP port |
Specify the TCP port number through which Trap Receiver will communicate with AppManager. The default is port 2735. |
|
Event Notification |
|
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Raise event if discovery succeeds? |
Set to Yes to raise an event if discovery is completely successful. The details of the event contain the list of discovered devices. |
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Event severity when discovery succeeds |
Set the event severity level, from 1 to 40, to indicate the importance of an event in which discovery succeeds. The default is 25. Discovery is successful if all devices in the device list are discovered and no errors occur. The event message indicates any duplicate IP addresses or hostnames. Duplicates are not considered to be an error. |
|
Raise event if discovery partially succeeds? |
Set to Yes to raise an event if discovery is partially successful. The details of the event contain the list of discovered devices and the discovery errors that occurred. |
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Event severity when discovery partially succeeds |
Set the event severity level, from 1 to 40, to indicate the importance of an event in which discovery partially succeeds. The default is 15. A partial discovery occurs if only some of the SNMP devices are discovered, or if the maximum device limit is reached. The event message indicates any duplicate IP addresses or hostnames. Duplicates are not considered errors. |
|
Raise event if discovery fails? |
Set to Yes to raise an event if no SNMP devices are discovered. The details of the event contain the discovery errors that occurred. |
|
Event severity when discovery fails |
Set the event severity level, from 1 to 40, to indicate the importance of an event in which no SNMP devices are discovered. The default is 10. |