Whether the level of expertise needed to circumvent logon authentication using Windows 95 is beyond the capability of a knowledgeable but non-expert user is a matter for debate. Similarly Macintoshes cannot be booted from the network and, although the file system may be more secure than that of MS-DOS and Windows 95, it is believed that authentication measures can be evaded without difficulty. Unix systems in general and, in particular, Linux systems do not in themselves present a problem. If it can be guaranteed that the system booted is the uncorrupted system intended by the administrator, then the ordinary user can be authenticated and constrained adequately. It should be noted that personal computers which are configured with multi-boot capability are, of course only as secure as the least secure operating system which can be booted.
Considerable expertise is needed to configure systems sensibly, whatever the operating system.
One cannot, in general, expect the average institutional computer officer to be sufficiently expert in all operating systems and network technologies. Firewalls A firewall cooperating with an authentication server could be used to prevent traffic from systems being used by unauthenticated users. This might be possible now for certain systems and further study is required to determine the current state of the art in this area. Although it is generally accepted that no special security measures over and above normal wiring practices are needed for the physical network in HEI environments, consideration must be given to unprotected network outlets because of the availability of portable computers. Systems which can alter their MAC addresses will cause problems for secure hubs.