What is SIM lock in Samsung Smartphones?

SIM lock is the highest security provision of a hand set. If you activate SIM lock, then you can use only that SIM (which is present during SIM lock activity) with the handset and if you insert any other SIM, then you need to provide the SIM lock password. If you forget the password, then you need to visit your Samsung Authorized Service Center to unlock it.

NOTE : In case you want to find your PUK Number, you can contact your Service Provider.