The customer using IC2 captive portal to limit the usage quota on clients connected behind Peplink router LAN port with open access.
The daily quota limit is base on per user but not bind to a particular LAN port or VLAN(Subnet).
E.g. If customer when to limit all users connect via port one(Or VLAN), the only way is all the users must connect via an external router(NAT) and then to one of the LAN port of Peplink router so that Peplink only see one user(WAN IP of the external router) then the quota impose will be possible on the particular LAN port or IP address, i.e. aggregated quota from all the clients connected via the LAN port.
Also it will be good that monthly quota in additional to daily quota reset can be implemented in this case as almost all captive portal support daily quota instead of monthly quota reset.