block users on-the-fly

["Guilherme Franco" <guilhermefranco@gmail.com>]

Hi,

Does anyone already have a program to block freeradius on-the-fly?

ie: user has PAID = YES in radcheck table. Whenever I set PAID = NO,
the user would no longer authenticate the next time he/ she logs in.
OK, this works, but, if the user is already loged in, even if I set
PAID = NO, the user would not be rejected (for obvious reasons). This
is important because the grand number of Router mode ADSL users, that
never logs out. I'm building a program to verify every x minutes the
database and if PAID = NO, return a flag to freeradius and then reject
the user.

Is there any other means to do that?

Thanks.