Using tcpdump on bigpipe?

I am just starting out with F5 BigIP. So bare with me.

We've recently migrated URLs off of our old GTM appliance to a new box. We asked our counterparts in another country to point their global DNS servers to the IPs of the new boxes.

My boss asked me to check if our old GTM is still receiving traffic from those global DNS servers. The old GTM is using the bigpipe CLI. I attempted to use tcpdump command strings to check if the listeners on the old GTM are still getting hits, but bigpipe does not seem to like tcpdump.

Does tcpdump even work on bigpipe? If so, can anyone give me the correct syntax to make it work properly?

Thank you.