I need to capture traffic on a voice vlan using wireshark. How do I get the switch to let me access that traffic with out it putting my PC on the Data vlan? Right now the switch is configured to only let cisco phones access the voice vlan. I also have bduguard enabled.
If you want the entire VLAN you won't get this information. If you just want the information for broadcast and unicast to the PC and phone, this should work without additional configuration.
If this is CUCM, you need to go to the phone webpage and enable "SPAN To PC Port" and then save and reset the phone. Settings->Device Settings->Ethernet Information->Span to PC port = true
Then it should work as described.
When you specify a port as a SPAN destination, it will not get an IP address. You will specify in the monitor session commands which VLANs you would like to send to that port.
Note: when SPANing a VLAN, you should either specify in or out. If you do 'both' (default) you'll get duplicate packets.