it says that for PPP, we should choose "other" in the type, but "other" means "don't bother checking, I believe what radutmp says". So which means if a user has a "stuck" entry in the session database she will not be able to login again. And I have met such problem also. When the wifi sudden shutdown or disconnect, which will leave the record of the user still online in the database, I have to clear it up manually, that 's not convenient. So what should I do with PPTP+PPP+Freeradius+MySQL when I have to set the simultaneous-use = 1 -- *Space Lee*