Troubleshooting SNMP and WMI connections

If you experience connection problems when connecting to a device via the Web Task Manager, Web Performance Monitor, or any other WhatsUp Gold feature that uses WMI or SNMP, please consult the lists below to troubleshoot the problem.

Troubleshooting a WMI connection

Important: You must have administrative credentials to establish WMI connections. For more information, see Using Credentials. Also, see Microsoft article 875605.

• Establishing a WMI connection can be very slow.

  This slow connection time can worsen when attempting to connect with devices running Microsoft Vista.

  We recommend that you open RPC port 135 on both the WhatsUp device's firewall and the firewall for device to which you are attempting to connect. Also be sure to open this port on any firewall between the connecting devices. Refer to the operating system Help for more information.

• Connected devices that are running different versions of Microsoft software (i.e. - Microsoft XP and Vista) may experience delayed or slow communication.
• WMI over VPN connections can take up to 120 seconds (possibly longer) to establish an initial connection. After the initial connection is made, subsequent connections take 8 to 10 seconds.
• Again, we recommend that you open RPC port 135 on each device's firewall, and any firewall between the connecting devices.
• A WMI memory leak exists in Windows 2003 and XP. Microsoft has developed hotfix 911262 that minimizes the leak in XP, and completely fixes the leak in Windows 2003.

For more information regarding WMI and connection problems, see Microsoft articles 389290, 389286, and the section entitled "I can't connect to a remote computer" in the Microsoft Script Center article, "WMI Isn't Working!".

Troubleshooting an SNMP connection

Important: The SNMP Trap Listener must be enabled to collect data for the SNMP Trap Log. To enable the WhatsUp Gold SNMP Trap Listener, the Microsoft SNMP Trap Listener must be disabled. Also, be sure to open SNMP port 162 for incoming SNMP traps.

• If you receive invalid values when attempting to monitor the IfOperStatus OID from a device running Vista, download Microsoft's hotfix 935876 to solve the problem.
• If you experience connection problems with a specific device, ensure that the device has SNMP enabled. Also ensure that SNMP port 161 is open on the device you are attempting to monitor.
• If you get what looks like a "stair-step" in your CPU and Process Utilization graphs, this is caused by Microsoft's 60-second polling interval. Increasing WhatsUp Gold's polling interval could help compensate for the lengthy Microsoft polling interval.
• Similarly, if you experience delays and/or unexpected, weird spikes in your graphs, try increasing the polling interval.