I've just read a similar post from MrSaffron from 2014, a rookie question, how are you protecting your network if the firewall is switched off?
Edit: I didn't think there was a firewall on the modem but there might be, I'll check properly tomorrow
The Asus firewall is in addition to the firewalling effect you get from network address translation (NAT) where a single IP address is shared with your domestic network. If you are with one of the less common ISPs whom can provide a routed subnet, then you have a more advanced setup.
Currently I'm only suggesting this as an option to see if it works, if it does you might need to add a rule to permit the BQM. The problem with most domestic (rather than enterprise grade) is the amount of customisation is limited.
It depends what you are protecting inside your network, depending on the number of users and their internet experience. If you have a house with some 40+ year old IT professionals it would be different to a family of children / teenagers whom do not understand internet risks.
The modem cannot have a firewall enabled as it doesn't see the internet TCP/IP traffic. It only handles the wholesale network / ISP internal layer, acting as a bridge between the Ethernet layer and the DSL layer. The PPPoE login that you define in the Asus is where the internet TCP/IP connection "exists" and the PPPoE is a link between your Asus and the ISP's boundary.
80/20 (2/jun/14) at 470m - Sync history highest: 64/9 (Sep/17), 54/6 (Jan/19), 51/6 (Mar/19)
20 years of broadband from 1999's ntl:cable modem trial - Live BQM