Packet sniffing tool does not sniff all network traffic through port mirroring on a virtual machine that is hosted by a Windows Server 2012 Hyper-V server

Applies to: Windows Server 2012 DatacenterWindows Server 2012 DatacenterWindows Server 2012 Standard


Consider the following scenario:
  • You create a virtual machine (VM) on a Windows Server 2012-based server that has the Hyper-V server role installed.
  • You connect the VM to a virtual switch that is connected to a physical network.
  • You have two computers (computer A and computer B) that both connect to the physical network.
  • The two computers and the VM are in the same subnet.
  • You set Mirroring Mode to Destination under the Port Mirroring section of Advanced Features in the VM's network settings.
  • You run a packet sniffing tool on the VM.
  • You ping computer B from computer A.
In this scenario, the packet sniffing tool does not capture the packets between computer B and computer A.


This issue occurs because the virtual switch does not deliver the packets to the mirroring destination port.


Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

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, contact 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 apply this hotfix, you do not have to make any changes to the registry.

Restart requirement

You might need to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.


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