Example: monitoring TCP connections established for a device

Too many TCP connections can signal that a device is being maliciously used, in the case of a workstation, or that your web server is close to maxing out, indicating the need to initiate a backup server. You can create an SNMP active monitor to watch a range of established TCP connections for a particular device. If the number of connections goes above the range you specify, you can be notified by an associated action.

To configure a TCP monitor:

1. From the WhatsUp Gold web interface, click GO. The GO menu appears.
2. If the WhatsUp section is not visible, click WhatsUp. The WhatsUp section of the GO menu appears.
3. Select Configure > Active Monitor Library. The Active Monitor Library dialog appears.
4. Click New, select SNMP Monitor, then click OK. The Add SNMP Monitor dialog appears.

   

5. Enter a Name and Description for the monitor. For example, Number of TCP connections less than 2000.
6. For the Object ID and Instance, click the browse (...) button, then locate the TcpCurrEstab (1.3.6.1.2.1.6.9) SNMP object in the MIB object tree.
7. Select Range of Values from the type drop down menu and enter 1999 (the maximum number of established TCP connections) as the High value and 0 as the Low Value, then click OK. An associated action will fail when the number of established TCP connections reaches 2000.
8. Test the newly created active monitor and make appropriate changes if needed.
9. Assign the active monitor to the web server:
   1. Right-click on the device on the appropriate device, then select Properties > Active Monitors. The Device Properties Active Monitor dialog appears.
   2. Click Add.
   3. Using the configuration wizard, create or select an action to notify you when the number of established TCP connections reaches 2000.

See Also Using the SNMP Monitor Selecting an object in the MIB Tree Example: monitoring network printer toner levels