We have been using Mikrotik Routerboards as NAS on various sites with a Radius server at the backend. I am facing this issue on one of the sites where we are using an RB450G as the NAS. The dynamic queues generated when a user logs in is proper but users tend to overshoot their allotted quota eg a user allotted 256k/256k ends up drawing 4M/2M and even more. I checked the forums and it was mentioned that "USE IP Firewall" in Bridge settings causes this so we have to disable it for PPPoE queues to work properly. I'm using RouterOS version 5.20 and this option is disabled by default so I've hit a dead-end. Any help would be welcome.