In my environment User have csh have default shell. In some cases some users requires KSH. We are using NIS as well as some local users. here my problem is recently in some of sun servers if users who have ksh as a default shell are trying to login with putty the session terminated after giving the password. if you login with any other user which not ksh as default shell and try to su to ksh users they can login. Please help in this.