EXOS Packet Capture

[Stefan_K_]

Hello,

today I played around with the built-in packet capture of EXOS ( How To: How to perform a local packet capture on an EXOS switch | Extreme Portal (force.com) )

I’m able to capture packets and open the pcap file with wireshark, but I only see the following packets:

Wondering if I’m doing something wrong or if the feature is something else than I’m thinking. Any hints?

Best regards
Stefan

[CThompsonEXOS · Accepted solution]

Hi,

You can use the editcap tool to remove the first 52 bytes.  Mine looked something like below from Powershell:

PS C:\Program Files\Wireshark> .\editcap.exe -C 52 editcap.pcap newpcap.pcap

syntax below:
PS C:\Program Files\Wireshark> .\editcap.exe -C 52 <original pcap filename> <new pcap filename>

Below is more on editcap:

https://www.wireshark.org/docs/man-pages/editcap.html

Before:

After:

Thanks,

Chris Thompson

[booflix]

From what you described, it sounds like the packet capture itself is working, since you’re able to export the pcap file and open it in Wireshark. When only a limited or unusual set of packets appears, Flixer it’s often related to where the capture is attached or what traffic actually passes through that point on the switch.

[booflix]

from what you’re describing, it doesn’t sound like you’re doing anything wrong—it’s more about how the EXOS packet capture feature actually works under the hood. Flixtor  The built-in capture on EXOS switches is fairly limited compared to something like a full span/mirror session feeding into Wireshark.

In many cases, EXOS captures are restricted to CPU-bound traffic (control plane) rather than full data plane forwarding. That means you’ll mostly see things like ARP, LLDP, STP, or other management/control packets, which would explain why your capture looks “incomplete” or not what you expected.

[Stefan_K_]

Hi Chris,

thanks for your quick reply! I’m on 30.7.1.1-patch1-86. Switch is an X460-G2. I’m just doing some testing of this feature and don’t want to capture any specific traffic for now. But we might need this feature in the near future. (Troubleshooting at a customers site)

Best regards
Stefan

[CThompsonEXOS]

Are you on 30.x or newer?  IIRC some bytes need to be stripped to be read properly if so.  

Generally it’s used for troubleshooting and debugging:

Be Aware!
Debug commands are primarily meant for trouble shooting purposes and are NOT part of any EXOS validation tests (regression).
The usage of any debug command can result in unexpected side-effects (like memory depletion, high CPU, process failures).

Is there a certain type of traffic you are trying to capture?

Thanks,

Chris Thompson