Front cover - IBM Redbooks

1.2.3 IT infrastructure
12 Lotus Security Handbook
thus connect two machines in that manner, the minimum definition of a network
is two devices.
For the purpose of this redbook, it is assumed that a network is more than two
computers exchanging data over a single cable. The scope includes two or more
computers utilizing any and all connectivity and telecommunication devices, such
as hubs, routers, gateways, switches, and so forth.
The definition of IT infrastructure is broader than that of a computer system or a
computer network.
The IT infrastructure includes all the components used for the processing and
transmission of information in an organization. It includes also all the devices that
provide additional services, for example:
► Backup devices (such as tape drives, tape robots or silos)
► Security devices (for example, proxies and firewalls)
► Special-purpose devices (printers, scanners, and so forth)
In addition, the definition of IT infrastructure also encompasses all the computer
networks in the organization and includes, as well, proprietary networks that
interconnect the organization with partner organizations (for instance, suppliers).
This last type of network is called an extranet. Where an extranet fits into an
organization’s IT infrastructure depends largely on the amount of control the
organization has over it.
Finally, the definition of IT infrastructure also includes boundary networks
between the internal, generally trusted network and the external, generally
untrusted Internet.
1.2.4 Computer security
The National Institute of Standards and Technology (NIST) has written a
document titled “An Introduction to Computer Security: The NIST Handbook”
(Special Publication 800-12). A PDF version of this document can be freely
downloaded at the following URL:
http://csrc.nist.gov/publications/nistpubs/800-12/handbook.pdf