How to set a static (fixed) DCOM port for WMI in Windows (4289831)

WMI runs as part of a shared service host with ports assigned through DCOM by default. However, users can set up the WMI service to run as the only process in a separate host and specify a fixed port.

IMPORTANT: A single Linux Foglight Agent Manager can handle up to 75 Windows agents (either SQL Server agent or Infrastructure agents) using WMI. As a result, when using WMI the number of Linux Foglight Agent Managers (FglAMs) is determined by the number of Windows agents divided by 75; for example, monitoring 300 Windows agents requires at least four (4) Linux Foglight Agent Managers.

This limitation does not apply to Windows Agent Managers. Quest R&D has successfully tested up to 2000 agents using WMI (i.e. 1000 database agents + 1000 WindowsAgents) using a single Windows Agent Manager.

How to set a static (fixed) WMI port for Windows 2008 R2 and higher

Step 1 - Host the Windows Management Service in a Standalone Host Process

From an elevated command prompt, run the following command

winmgmt -standalonehost

Note: This will set the static port by default to port 24158.

Step 2 - Restart the WMI Services

Stop the WMI service by typing the command net stop "Windows Management Instrumentation", or use the short name of net stop winmgmt

Restart the WMI service again in a new service host by typing net start "Windows Management Instrumentation" or net start winmgmt

Optional Step 3 - Set the TCP Port (this step is only necessary if configuring a static WMI port that is not 24158)

Launch the Component Services from the Command Prompt, or using the Run command

From Component Services, navigate to Computers\My Computer\DCOM Config\Windows Management & Instrumentation

Right click on Windows Management and Instrumentation and select Properties

Click the Endpoints tab and the Properties button

Set the TCP port to desired fixed WMI port

Click OK, then Apply, and then OK

---- If you are not using the Windows firewall on the remote host, this task is complete.

---- Please note that for external firewalls, an opening to the host for TCP port 135 for inbound successful WMI communications

Step 4 - Add an incoming WMI rule in the WIndows Server Firewall for the static port. 

netsh firewall add portopening TCP 24158 WMIFixedPort

Note: In this example, the static port used is 24158 and the rule name has been set to "WMIFixedPort". These values can be changed if necessary.

Undoing these changes

To revert to the default Windows WMI port behavior, run this command from an elevated command prompt:

winmgmt -sharedhost 

To remove the firewall rule set in Step 4, run this command from an elevated command prompt:

netsh advfirewall firewall delete rule name="WMIFixedPort"

Troubleshooting this connection

A). If validating this connection using the Foglight database cartridge connection fails, please confirm that the Windows firewall also contains a firewall rule for the database agent, for example a SQL Server default instance connecting using port 1433 or an Oracle agent connecting using port 1521. The validation utility must establish a database connection successfully first, prior to attempting an OS connection.

B). WMI also requires a firewall port to be opened using port 135. By default, on the Windows Firewall there should be several rules enabled to allow inbound connections for TCP port 135 for the Windows OS svchost.exe application.

IMPORTANT: A single Foglight Agent Manager can handle up to 75 Windows agents (either SQL Server agent or Infrastructure agents) using WMI. As a result, in Windows environments using WMI, the number of Foglight Agent Managers (FglAMs) is determined by the number of Windows agents divided by 75; for example, monitoring 300 Windows agents requires at least four (4) Foglight Agent Managers.

If you are monitoring more than 75 agents running on a Windows System (FglAM), the monitored hosts should be configured to use WinRM.

Please consult the latest version of the Foglight Agent Manager User Guide for more details on configured WMI and WinRM to monitor Windows hosts.

Source: MSDN