Looking for a good Linux solution for the local kiddies internet workshop. They have been terrorised for years with WinBlowz and it's time for a change.
But, it's not so easy, because there are certain terms that need to be met:

-> Centered user database (accessible via LAN) for access from various terminals

-> Daily time restriction

-> Different privilages for different users

In another words, user should be able to login at terminal A at any time, spend 30 minutes and leave. Later on, he comes to terminal B, and he then has only another 30 mins to spend (if the daily limit is 1 hour/user).

That's the basic problem i've been puzzled with so far. Back on windows, job was done by an app called "Watchdog".
I'm trying to think of a Linux solution, there are some mentiones of time restrictions on various forums by using PAM. But how to make it all tick while using a centered user database?

I'm open to any suggestions/ideas. Thnx.