Port mirroring on 5312 IP phone

[jphillips]

I've enabled the Port Mirroring option on a Mitel 5312 phone, assuming it will send all packets at the network interface to the PC interface.  I would then capture using Wireshark on my PC.

Unfortunately, Wireshark isn't capturing any new traffic after I enable mirroring.  I only get the usual traffic to/from my PC's address, and broadcast/multicast traffic.  I don't see any unicast traffic to/from the phone.

I'm curious whether this is a side-effect of our network config.  We use Cisco Catalyst 2960-X switches, with default VLAN 1 and voice VLAN 9.  Ports are configured with "switchport voice vlan 9", so the phones are identified by the switch and placed on VLAN 9 -- but the PC connected through the phone is on VLAN 1.

My hypothesis is that phone data is using 802.1q-tagged packets, which my PC NIC is ignoring.  Normally my Intel NIC can support VLAN tagging, but the driver is currently broken by the latest Win10 release, so I can't just try it out.

Or could there be something else I'm doing wrong?

[Dogbreath]

Try booting off a Linux live image [CD or USB stick] and re-testing, if you think it's a NIC driver issue.

[jphillips]

Thanks Dogbreath, good idea.  I finally got around to trying that, but the packet flow seemed the same as from within Windows.  There was absolutely no traffic from the voice subnet, only broadcast/multicast and whatever reached my PC from the default VLAN.  I tried making calls too, just to be sure there was voice traffic.

I also looked for traffic to/from my phone's MAC address, but there was none.  Although I expect the PC port's MAC is different from the LAN port's, and that this is normal.

I know that the simple solution now is to find an ethernet hub to put between my phone and the LAN, but this port mirroring feature seems to work for everyone else, so it's driving me nuts that I can't get it going.