user is logged from 3 different devices when he logged out from one system we need to do restrict to other devices in dot net

why 'in dot net' ? - I would have thought a simpler approach would have been to use MS Active Directory for example

lets face it - if you're going to do this in Dot Net, you'd need to write and deploy a new GINA (better in c++ anyway), that checks a central repository/database of user/device/restrictions .. which sounds a lot like directory services