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How can I display Broadcom Ethernet Adapter VLAN tags in a packet sniffer sensor?



We use a custom packet sniffer sensor to collect IEEE 802.1Q VLAN information on our network. The VLAN tags are correctly displayed in the according toplist when setting the sniffer sensors up using any network card but not when monitoring traffic that passes a Broadcom Ethernet Adapter.

What can I do to show VLAN information tags of a Broadcom Ethernet Adapter?

broadcom ethernet network-card packet-sniffer packet-sniffing prtg traffic vlan vlan-information vlan-tags

Created on Feb 19, 2015 5:14:40 PM by  Gerald Schoch [Paessler Support]

Last change on Feb 19, 2015 5:21:53 PM by  Gerald Schoch [Paessler Support]

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Accepted Answer



This article applies to PRTG Network Monitor 14 or later

Showing VLAN Tags of a Broadcom Ethernet Adapter

If you monitor data packets that pass your Broadcom Ethernet Adapter using the Packet Sniffer (Custom) Sensor, you will not be able to simply show VLAN information tags in the packet sniffer toplist. You will see an empty column in the toplist table instead. This is not an issue of PRTG, but Broadcom Ethernet Adapters discard the 802.1Q headers by default.

To cause the network card not to strip these headers, you have to edit the Windows registry. Please see the following article for detailed instructions:

Caution: Please back up your system before manipulating the Windows registry!

Created on Feb 19, 2015 5:17:50 PM by  Gerald Schoch [Paessler Support]

Last change on Feb 19, 2015 5:20:49 PM by  Gerald Schoch [Paessler Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.