Timbuktu Pro allows you to specify many different levels of remote-user access. You can allow all users to access certain services, and limit other services to password-authenticated users.
There are three main kinds of remote users: Guest Users (which include Ask for Permission Users and Temporary Guests), Registered Users, and Windows NT Users.
Timbuktu Pro's Connections menu lists all current users (see Monitoring Remote Connections) and allows you to disconnect any or all of them at any time.