This article describes a problem in which Network Load Balancing (NLB) cluster communication gets interrupted randomly in Windows Server 2012 R2. An update is available to fix this problem. Before you install this update, see the Prerequisites section.
This problem occurs when a security feature is enabled in your environment to prevent MAC impersonation and when an NLB cluster is set to operate in Internet Group Management Protocol (IGMP) multicast mode. In this configuration, the IGMPv1 multicast membership reports are randomly sent by having an incorrect source MAC address. This situation interferes with the security settings of the intermediate devices that are used, and this breaks the cluster communication.
How to get this update
Important If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.
Method 1: Windows UpdateThis update is provided as a Recommended update on Windows Update. For more information on how to run Windows Update, see How to get an update through Windows Update.
Method 2: Microsoft Download CenterThe following files are available for download from the Microsoft Download Center.
For more information about how to download Microsoft support files, select the following article number to view the article in the Microsoft Knowledge Base:
|All supported x64-based versions of Windows Server 2012 R2||Download the package now.|
119591 How to obtain Microsoft support files from online servicesMicrosoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.
Update detail information
PrerequisitesTo install this update, install April 2014, update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 (2919355) in Windows Server 2012 R2.
Registry informationTo apply this update, you don't have to make any changes to the registry.
Restart requirementYou may have to restart the computer after you apply this update.
Update replacement informationThis update doesn't replace a previously released update.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
The English (United States) version of this software update installs files that have the attributes that are listed in the following tables. The dates and times for these files are listed in Coordinated Universal Time (UTC). Be aware that dates and times for these files on your local computer are displayed in your local time and with your current daylight saving time bias. The dates and times may also change when you perform certain operations on the files.