I have a SPAN monitor session setup to capture both tx/rx on a port 9 (see below). And I can see the multicast count ticking up on port 9. But none of the multicast packets show up in the SPAN session (and they don't seem to be making it across the switch). How can I figure out what's going on?

Another baffling thing is that, if instead of connecting to the port 9 directly, I connect through another small dumb switch (and then to the Catalyst), things seem to work. The multicast frames show up in the SPAN session, and they show up at the other end.

SwitchB#show monitor session 1
Session 1
Type                   : Local Session
Source Ports           : 
    Both               : Gi0/9
Destination Ports      : Gi0/10
    Encapsulation      : Native
          Ingress      : Disabled
  • You should post the c2960's configuration Jul 3, 2018 at 23:36
  • I figured out what was going on. Some stupid thing. Thanks for your help.
    – Ziffusion
    Jul 4, 2018 at 3:52


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