KB 2885541 Packet sniffing tool does not sniff all network traffic through port mirroring on Windows 2012 Server VMs

A recent bug fix lead to a new hotfix KB2885541 for Windows Server 2012 (Windows Server 2012 Datacenter and Windows Server 2012 Standard)

It occurs when:

• The VM is hosted on Server 2012
• The VM is connected to a virtual switch which connects to a physical network.
• 2 PCs connect to the physical network.
• VMs and PCs are on same subnet.
• You set Mirroring Mode to Destination under the Port Mirroring section of Advanced Features in the VM’s network settings.
• The packet sniffing tool is run in the VM.
• And ping PC B from PC A.

Download it here https://support.microsoft.com/kb/2885541