Sometimes, it might be necessary to protocol / log / record the way traffic has been sent or received within your network. Setting this up is not very hard, but you have to know very well where to search for it - this tutorial is supposed to make life a bit easier in that respect.
Traffic Log on a firewall e.g. USG, has to be set to be saved on some sort of external logging destination - this could a USB stick plugged into the USG, or a NAS server connected to the network - the firewalls' own System Log unfortunately cannot save the traffic log.
To Activate USB storage navigate to: (and tick the box)
Configuration > System > USB Storage
In order to save the traffic log, navigate to:
Configuration > Log & Report > Log Settings
Double click or select and press the "Edit"-Button now either on
USB / Remote Server 1/2/3/4
There, you may find traffic log on the following path
Active Log > Network > Traffic Log
Here you now can set the logging level via the bullet points. Also view this screenshot as reference:
That should be all there is to it! You from then onward should be able to see in the logs the Source IP, Destination IP as well as other traffic related information!
You can find the stored logs under:
Maintenance > Diagnostics > System Log