You are currently offline, waiting for your internet to reconnect

Your browser is out-of-date

You need to update your browser to use the site.

Update to the latest version of Internet Explorer

Virtual switch extension cannot send packets separately through every individual network adapter in Windows Server 2012

Consider the following scenario:
  • You have a virtual switch extension installed on a Windows Server 2012-based Hyper-V server.
  • The extension sends packets that contain one or more of the following flags: 



In this scenario, the packets are sent by using the same network adapter in the virtual network.
This issue occurs because Network Driver Interface Specification (NDIS) chains the Net Buffer Lists (NBLs) incorrectly.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there is a "Hotfix Download Available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website: Note The "Hotfix Download Available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.


To apply this hotfix, you must be running Windows Server 2012.

Registry information

To use the hotfix in this package, you do not have to make any changes to the registry.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.
Windows Server 2012 file information notes
Important Windows 8 hotfixes and Windows Server 2012 hotfixes are included in the same packages. However, only "Windows 8" is listed on the Hotfix Request page. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 8" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.
  • The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
    VersionProductMilestoneService branch
    6.2.920 0.20 xxxWindows Server 2012RTMLDR
  • The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2012" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
For all supported x64-based versions of Windows Server 2012
File nameNdis.sys
File version6.2.9200.16548
File size998,632
Date (UTC)05-Mar-2013
Time (UTC)08:08
File nameNdistrace.mof
File versionNot applicable
File size4,548
Date (UTC)06-Jul-2012
Time (UTC)20:10
PlatformNot applicable
File nameNdis.sys
File version6.2.9200.20651
File size993,512
Date (UTC)05-Mar-2013
Time (UTC)07:13
File nameNdistrace.mof
File versionNot applicable
File size4,548
Date (UTC)06-Jul-2012
Time (UTC)19:53
PlatformNot applicable

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
More information
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates

Additional file information

Additional file information for Windows Server 2012

Additional files for all supported x64-based versions of Windows Server 2012
File nameAmd64_microsoft-windows-ndis-minwin_31bf3856ad364e35_6.2.9200.16549_none_b24f6a87b1ab4af1.manifest
File versionNot applicable
File size246,273
Date (UTC)05-Mar-2013
Time (UTC)08:12
PlatformNot applicable
File nameAmd64_microsoft-windows-ndis-minwin_31bf3856ad364e35_6.2.9200.20653_none_b2c835aacad66ea2.manifest
File versionNot applicable
File size246,273
Date (UTC)05-Mar-2013
Time (UTC)07:39
PlatformNot applicable

Article ID: 2823958 - Last Review: 04/09/2013 21:08:00 - Revision: 1.0

  • Windows Server 2012 Datacenter
  • Windows Server 2012 Standard
  • kbautohotfix kbqfe kbhotfixserver kbfix kbsurveynew kbexpertiseadvanced KB2823958
ript' src='" + (window.location.protocol) + "//'><\/script>");