SPANing Tree is just a protocol to prevent network loops, which i take you allready know.. as far a sniffing traffic from multiple VLAN's .. you need to do port mirroring.. just make one port on your switch (let's say port f0/1)a mirror port for all ports in all VLAN's. This will send a copy of all traffic from all ports in all VLANS to port f0/1. Plug your sniffer in port one and you should see traffic.. you perform this task in #config int mode its called (port monitor FastEthernet0/1, '' f0/2, etc etc etc..)let me know how it goes. I am doing the same thing on my network.. it works like a champ.. Good Luck -Catfisch
commands you show are what is needed to setup SPAN
ports. However, the Cisco documentation for the
2900 and 3500 series routers say a SPAN port cannot
monitor ports across VLANs. see below
Is your switch configured with more than one VLAN?
Cisco excerpt follows ...
You can use Switch Port Analyzer (SPAN) to monitor traffic on a given port by forwarding incoming and outgoing traffic on the port to another port in the same VLAN. A SPAN port cannot monitor ports in a different VLAN, and a SPAN port must be a static-access port. You can define any number of ports as SPAN ports, and any combination of ports can be monitored.
For the restrictions that apply to SPAN ports, see the Avoiding Configuration Conflicts section on page 9-2.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...