Reliability and scalability improvements in TCP/IP for Windows 8.1 and Windows Server 2012 R2

Applies to: Windows Server 2012 R2 DatacenterWindows Server 2012 R2 StandardWindows Server 2012 R2 Essentials


This article describes various network and computer issues that occur when TCP ephemeral ports are exhausted in Windows 8.1 or Windows Server 2012 R2. An update is available to fix these issues. The update also includes additional reliability improvements. Before you install this update, see the Prerequisites section.

Issues that are fixed in this update

Issue 1

Computer may crash with "0xd1" Stop error when a proxy application redirects UDP traffic.

Issue 2

Computer may crash with "0xA" Stop error during logon or logoff. 

Issue 3

When a computer that is running Windows 8.1 or Windows Server 2012 R2 runs out of or exhausts the number of TCP ephemeral ports, you may experience symptoms that resemble the following:
  • The computer crashes, freezes, or hangs.
  • The computer can't access the Internet or a network file share.
  • The computer can't log on to the domain.
Note You may experience other similar symptoms that are not listed here.


To resolve this problem, apply the update that is mentioned in the "How to get this update" section. After you apply this update, Windows 8 .1 and Windows Server 2012 R2 can reuse ephemeral ports without having to wait for the TIMED_WAIT state to expire.

Note To resolve this problem for Windows 8 or Windows Server 2012, see hotfix 3014399.

Note Windows Server 2016 supports the auto-reuse port range feature by default.

How to use this new feature

This new feature introduces the following two socket option settings:

    For a connection scenario to be implemented, the socket option must be set before you bind a socket. This option instructs the system to postpone port allocation until connection time when the 4-tuple (quadruple) for the connection is known.
  • Auto-reuse port range

    You can set the auto-reuse port range by using Windows PowerShell cmdlets. This separate port range is defined by the following two new TCP template parameters:
    • AutoReusePortRangeStartPort
    • AutoReusePortRangeNumberOfPorts
    You can set these parameters by using the PowerShell cmdlet Set-NetTCPSetting. The bounds for the smart port range are from port 1024 exclusive to port 65535 inclusive. The smart port range can partly cover the dynamic port range. In this case, ports that are in both ranges will be used only for smart port allocation.

    For an application to use these new socket parameters, the auto-reuse port range must be defined as in the following example:

    Set-NetTCPSetting –SettingName InternetCustom -AutoReusePortRangeStartPort 40000 -AutoReusePortRangeNumberOfPorts 1000

Note Restart requirement: You have to restart the computer after you change the AutoReusePortRange settings for the settings to take effect.

After the restart, you can verify your defined settings using the PowerShell command:


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 Update Catalog

To get the stand-alone package for this update, go to the Microsoft Update Catalog website.

Update detail information


To install this update, you should first install April 2014, update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 (2919355) in Windows 8.1 or Windows Server 2012 R2.

Registry information

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

Update replacement information

This 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.


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.