NLB cluster communication gets interrupted when MAC impersonation security feature is enabled in Windows Server 2012 R2

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.

Symptoms

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 Update

This 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 Center

The following files are available for download from the Microsoft Download Center.

Operating system

Update

All supported x64-based versions of Windows Server 2012 R2

Download Download the package now.

For more information about how to download Microsoft support files, select the following article number to view the article in the Microsoft Knowledge Base:

119591 How to obtain Microsoft support files from online services Microsoft 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

Prerequisites

To 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 information

To apply this update, you don't have to make any changes to the registry.

Restart requirement

You may have to restart the computer after you apply this update.

Update replacement information

This update doesn't replace a previously released update.

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

References

Learn about the terminology that Microsoft uses to describe software updates.

File Information

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.

Notes

  • 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.

    Version

    Product

    Milestone

    Service branch

    6.3.960 0.18xxx

    Windows Server 2012 R2

    RTM

    GDR

  • GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.

  • The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed in the "Additional file information" section. MUM, MANIFEST, and the associated security catalog (.cat) files, are very 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.

x64 Windows 8.1 and Windows Server 2012 R2

File name

File version

File size

Date

Time

Platform

Nlb.sys

6.3.9600.18183

337,408

28-Dec-2015

22:58

x64


x64 Windows 8.1 and Windows Server 2012 R2

File property

Value

File name

Amd64_14b74b7fe21f0785a6fabecb2fc2f364_31bf3856ad364e35_6.3.9600.18185_none_b9a15354fdd295a3.manifest

File version

Not applicable

File size

726

Date (UTC)

30-Dec-2015

Time (UTC)

23:19

Platform

Not applicable

File name

Amd64_microsoft-windows-n..ncing-networkdriver_31bf3856ad364e35_6.3.9600.18185_none_9ec926d2ec60505f.manifest

File version

Not applicable

File size

2,708

Date (UTC)

30-Dec-2015

Time (UTC)

15:34

Platform

Not applicable

File name

Update.mum

File version

Not applicable

File size

1,599

Date (UTC)

30-Dec-2015

Time (UTC)

23:19

Platform

Not applicable


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