An Introduction to WMI Version 7.2
Contents About this Guide 3 What is WMI? 3 How is WMI Structured? 3 How Does N-central use WMI? 5 WMI and Network Discovery 5 WMI and Monitoring 5 N-central SDK 5 Appendix: Viewing WMI Namespaces and WMI Data 6
About this Guide WMI is a Microsoft-specific protocol that is used to monitor and manage Windows devices. N-central uses WMI to discover valuable Windows device asset information, such as serial numbers and installed hot fixes, and to monitor the performance and health of Windows servers, workstations, and laptops. This guide is intended for a technical audience that is using N-central to monitor and manage networks and is unfamiliar with WMI. This guide provides the following: An explanation of WMI How N-central uses WMI to gather device asset information and monitor devices How to setup WMI on a Windows device This guide is current as of Wednesday, January 26, 2011. What is WMI? WMI (Windows Management Instrumentation) is a network-based, Windows-specific protocol. The N-central Windows agent and Windows probe use WMI to query Windows devices for information. WMI also allow scripts and applications to be remotely run on a Windows device. WMI is available on Windows 2000, 2003, 2008, XP, Vista, and Windows 7. It is unavailable on Windows XP Home and Windows Vista Home. Is WMI secure? WMI is a very secure protocol. In order to access WMI data, the application requesting the information (for example, the N-central Windows agent or Windows probe) must be either installed locally, or must provide Domain Administrator credentials if the request is being made remotely. How is WMI Structured? Data in WMI is grouped into WMI classes. For example, there is a WMI class for logical drives (Win32_ LogicalDisk), and there is a class for running processes (Win32_Process). WMI classes are then grouped into WMI namespaces. Most of the WMI classes exist under the root\cimv2 WMI namespace, but there are other namespaces (for example, root\microsoftexchangev2) that contain WMI classes related to a specific Microsoft application. - 3 -
WMI Folder Structure To locate find data, you can navigate through the hierarchy. For example, if you wanted to find out the amount of free disk space of a logical disk, you would navigate through the following: root\cimv2 namespace>win32_logicaldisk WMI>FreeSpace To look at it another way, WMI data is just like making a SQL query: Select FreeSpace from Win32_LogicalDisk where DeviceID= C:\ ; Where FreeSpace is the property being returned, Win32_LogicalDisk is the database table (called a WMI class), and DeviceID is the unique identifier of the disk. What is a WMI namespace? A WMI namespace is just a container for WMI classes. By keeping different WMI classes in different WMI namespaces, Windows allows you to specify different access permissions for different WMI classes. - 4 -
What WMI namespaces does N-central use? N-central uses the root\securitycenter namespace to gather antivirus information through the A/V Security Center service, and it uses the root\cimv2 namespace for all other WMI-based services. You can see a list of all of the available WMI namespaces on your computer by using the wmimgmt.msc command see To view WMI namespaces on a Windows device on page 6 for specific steps. How Does N-central use WMI? N-central uses WMI in two ways: it gathers data about Windows devices during a network discovery or when a Windows agent is installed it monitors the health and performance of Windows devices WMI and Network Discovery N-central uses WMI when a Windows probe does a discovery of a network, or when a Windows agent is installed on a device. The Windows probe and Windows agent use WMI to gather asset data, such as the operating system, number of hard drives, make/model, serial numbers, and amount of RAM. WMI and Monitoring The Windows probe and Windows agent use WMI to monitor the health and performance of devices. This includes hardware metrics such as CPU usage, memory usage, and disk usage, as well as software metrics such as the performance of an Exchange or Active Directory server. N-central SDK In addition to the many stock WMI-based services, if you host your own N-central server, you can use the N-central SDK to create customized WMI-based services that monitor applications, the Windows OS itself, or other important information on Windows devices. The N-central SDK is available for download from the N-able Resource Center at https://nrc.nable.com/support/softwaredownloads/pages/n-central_sdk_3-0.aspx. - 5 -
Appendix: Viewing WMI Namespaces and WMI Data To view WMI namespaces on a Windows device 1. From the Windows Start menu, click Start>Run. 2. Type wmimgmt.msc and click OK. 3. Right-click WMI Control (Local) and select Properties. 4. Select the Security tab. 5. Expand the Root folder. 6. All of the sub-folders underneath the Root folder are the WMI namespaces on the device. To view WMI data on a Windows device 1. From the Windows Start menu, click Start>Run. 2. Type wbemtest and click OK. 3. Click Connect. 4. Type root\cimv2 in the Namespace field. 5. Click Connect. 6. Click Enum Classes. 7. Select Recursive. 8. Click OK. 9. Double-click the WMI class you would like to view. For example, double-click Win32_LogicalDisk. 10. To view the data for a specific Logical Disk, click Instances. 11. Double-click the Logical Disk that you would like to view. For example, double-click Win32_LogicalDisk.DeviceID= C:. 12. In the Properties field, scroll down until you see the FreeSpace and Size metrics for this Logical Disk. Congratulations! You ve now successfully used the wbemtest command to view the size and remaining free space on the C: drive! - 6 -
Disclaimer This document may include planned release dates for service packs and version upgrades. These dates are based on our current development plans and on our best estimates of the research and development time required to build, test, and implement each of the documented features. This document does not represent any firm commitments by N-able Technologies Inc. to features and/or dates. N-able Technologies will at its best effort, try to meet the specified schedule and will update this document should there be any significant changes. N-able Technologies reserves the right to change the release schedule and the content of any of the planned updates or enhancements without notice. Publication or dissemination of this document alone is not intended to create and does not constitute a business relationship between N-able Technologies and the recipient. Feedback N-able Technologies is a market driven organization that places importance on customer, partner and alliance feedback. All feedback is welcome at the following email address: feedback@n-able.com. About N-able Technologies N-able Technologies is the global leader in remote monitoring and management software for managed service providers and IT departments. N-able s award-winning N-central platform and complementary toolsets, backed by best-in-class business and technical services, are proven to reduce IT support costs, improve network performance and increase productivity through the proactive monitoring, management and optimization of IP-enabled devices and IT infrastructure. N-able is 100% channel-friendly and maintains operations in North America, the U.K., the Netherlands and Australia. Copyright 2011 N-able Technologies All rights reserved. This document contains information intended for the exclusive use of N-able Technologies' personnel, partners, and potential partners. The information herein is restricted in use and is strictly confidential and subject to change without notice. No part of this document may be altered, reproduced, or transmitted in any form or by any means, electronic or mechanical, for any purpose, without the express written permission of N-able Technologies. Copyright protection includes, but is not limited to, program code, program documentation, and material generated from the software product displayed on the screen, such as graphics, icons, screen displays, screen layouts, and buttons. N-able Technologies, N-central, and N-compass are trademarks or registered trademarks of N-able Technologies International Inc., licensed for use by N-able Technologies, Inc. All other names and trademarks are the property of their respective holders.