State about the Single Sign-On Intranet
This Intranet, if managed efficiently, allows maximum security by firewalling anyone from inappropriate sites automatically. For example, the Railways.
It would be notable that any of the above Intranets can be controlled or firewalled through passwords and user IDs to safeguard security throughout an organisation. The fourth type of Intranet dispenses with individual log-ins or passwords opting instead for a single sign-on for all users and letting each system look-up the appropriate access privileges for each user.