I'm troubleshooting a problem with a host connected to my Nexus 56128. I would like to do a packet capture of the data going to that host. Is there an easy way to grap a .pcap file of this data from the switch?
you can use local tool inside switch to capture.
*** Rate All Helpful Responses ***
it appears that you can only capture control plane data with that tool. What I want to do is capture packets on the data plane from host to host.
Any thoughts on that?
You have 2 ways to accomplish this, the first is a classic monitor session where you mirror the traffic from one port(so the one where you host is connected) to a second port where you might have a sniffer attached(e.g a PC with wireshark running, or a linux box with tcpdump).
The second option is to use ELAM, this will not give you the full picture on the packets passing though as it will capture only a specific subset of traffic previously defined by a trigger with a filter.
You can find more details on ELAM here:
and on SPAN/monitor session here: