Comment by Johnie

For those interested, you can setup tcpdump on Asus router pretty easily to monitor traffic going through the router. You don't even need to mess with the firmware on the router.

1. Install Entware https://github.com/Entware/Entware/wiki/Install-on-Asus-stoc...

2. Then install tcpdump: `opkg install tcpdump`

From there, you can monitor any traffic going through your router.