There are many different ways to interact with the Network Security Toolkit once you've booted.

Regardless of the access method you choose, you will need to login. The default login ID is root and the default password is nst@2003. This combination is used regardless of whether you are logging in at the console, through a ssh connection, through a tightvnc connection, or via the Web User Interface. It is recommended that you use the nstpasswd script as soon as you login to change the password (this is described in Setting the Password (nstpasswd)).