Realtek NIC and no VLAN tag stripping

Brief post, cribbed from http://forum.gns3.net/topic7559.html and https://ask.wireshark.org/questions/5996/how-to-configure-realtek-pcie-gbe-family-controller-to-capture-vlan-tag-packet

  • Update drivers
  • Find reg sub-key under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002BE10318}
  • Add/update DWORDs:
    • MonitorModeEnabled = 1
    • MonitorMode = 1
    • *PriorityVLANTag = 0
    • SkDisableVlanStrip = 1

Basically, I had a PC running Windows 7 which was on a trunked switch port. I was expecting the native VLAN to work and remaining tagged traffic to not be visible. Turned out that the Realtek driver was stripping off the 802.1q VLAN tags and passing all traffic to the machine. The above settings resolved this.

Comments

One response to “Realtek NIC and no VLAN tag stripping”

  1. wjiang

    I have the same problem. Host is windows 10, with 4-port realtek nic card, and vm is ubuntu os. need to use one of the port as vlan trunk to the ubuntu vm.
    the nic is connected to a tagged port on ethernet switch.

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