Anyone know what the problem could be?
Without being an expert, the first thing that pops into my mind is the Captive portal settings:
Maximum concurrent connections - Default is to only allow 16 total connections to the portal's web interface. That means an absolute maximum of 16 people will be able to get to the portal in a given time period. This is probability #1 I think.
What
authentication means are you using? Internal user manager or RADIUS?
Are ALL the client PCs using
DHCP addresses? Is it possible some are setup with static IPs/DNS/gateway? DHCP is preferred, but the important thing is the DNS server on each PC needs to be set to the LAN IP of monowall in order to be re-directed to the portal. Do you have the
DNS forwarder turned on?
Do you have
multiple subnets or other routers on the LAN? You will need an outbound NAT rule to allow add'l subnets
How are you accomplishing the ban on uploading files larger than 100mb? I've never heard of any such capability on a network level. Pass thru MAC will just allow users to be able to access the Internet without having to authenticate with the captive portal - just as if the portal was not turned on.
Regards,
Aaron