Is there a way to identify the IP or source of internal LAN traffic?

[MakOwner]

I'm sure I'm probably posting this in the wrong forum, so slap my hand if needed.

I can't imagine that you'd want this running all the time, but is there something available that I can run on and tell how much data a given address is passing through pfSense?

for example, I notice in the Traffic graph 30 or 40 Mbs is passing through the firewall, and I want to identify the downloader …

[muswellhillbilly]

https://doc.pfsense.org/index.php/How_can_I_monitor_bandwidth_usage

Personally, I use NTopNG (located in the Packages section).

[KOM]

For just a quick check, go to Status - Traffic Graph.  Set Interface to LAN and Display to Host Name.

[MakOwner]

Thank you! Both excellent suggestions!