What are the simplest way to restrict the users

The simplest way to restrict the users to peek inside the internals of the Web site is to use firewalls, where the information cannot be seen or accessed from the Internet at large. Simple firewalls consist of software that prevents access to internal networks from the Internet. While general traffic such as email is allowed into the mail server, programs such as FTP clients, Telnet users or search engine queries cannot access machines beyond the safety premises of the firewall.