Disabling their port and punting them to customer support is NOT a cost efficient way of dealing with the problems, at least not in the market I am in.

It's like the car rental business. If you want to provide cars to people without a drivers license, then your customer support people will be busy whether or not you provide them with a competent driving service, i.e. a driver. In today's world ISPs provide Internet access services to people who are not competent to manage those services and it all ends in higher support costs somewhere along the way. But, if you would provide a MANAGED Internet access service where you install a gateway box that you can monitor and configure, now you are providing a real service to the customer. Since you can configure that box, you can identify potential bad traffic and throttle it rather than shutting down the entire gateway. Baddies will get no joy from hacking your customer and will go away. The vendors of little gateway boxes, generally DSL/Cable router/siwtch/modems, implement most of their functionality in software. If service providers demand a sensible box with firewall capabilities and remote monitoring/management by the service provider, then the vendors can quickly get a product to market. Yes, this is a higher end service because it is managed, but many have learned that specializing in high-touch services is a lucrative business. --Michael Dillon