Heads Up :
The post you are writing will appear in a public forum. Please ensure all content is appropriate for public consumption. Review the employee guidelines for the community here.
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 s...
Thanks for looking this up.
Turned out to be a stupid problem. There was a VLAN header on the frames that was causing the switch to drop them. SPAN wouldn't show these frames to me (don't know why), but counted them in the stats. Wireshark wouldn't...
@chrihussey
Yes, the device is on port 9, and the SPAN destination is port 10 (where I am sniffing the traffic). The eventual destination for the multicast traffic is elsewhere, across a couple of routers. I can see IGMPv3 and unicast in the SPAN j...
Yes, I disabled it because I wanted to eliminate that as the problem. But the behavior is the same in either case.
With IGMP snooping turned off, the switch ought to be flooding multicast to all ports, without looking for a listener.
Here is the output of "show interface <port> control".
Doesn't look like it's dropping traffic.But the multicast frames don't show up in the SPAN session, and don't seem to be switched.The multicast number does keep going up, so it's counting somet...
