On Border Manager or Netware, I would like to restrict a user to a set amout of MB's that can be downloaded. After that, their Internet access would be cut off.
Here are two solutions:
You can use the TrafficShaper for NetWare to do this, if short term quotas (hourly, daily, etc.) are acceptable for each workstation. It does not have an accounting system - i.e., it is not tied to a database that would allow you to implement long-term (over months / years). But you end up with the same effect - people who overconsume are punished.
But if you wanted to limit the amount of data per hour or day, etc. the TSE (Traffic Shaping Engine) can certainly do that. You can have it throttle back the speed or cut it off.
There is also a "bandwidth banking" feature so you can apply a very low data rate, unused bandwidth accumulates, and they can use that in a burst.
The same techniques can be applied to individual downloads ( TCP or UDP flows ) so that downloads larger than a certain size are interrupted or throttled.
It runs on your existing NBM server if you want, so no cost to give it a try.
See the Trapper program at http://www.kvy.com.ua/