Networks are comprised of many different pieces of hardware including workstations, servers, hubs, bridges, routers, and wireless access points.
Different security efforts have been applied to different aspects of the network, the two working together to provide a comprehensive security solution.
Information storage media exist in a variety of forms and can contribute to overall security if some basic steps are taken to manage data storage on the storage media.
Forms of external storage media range from small USB devices that are read/write capable, to CDs/DVDs which are read-only to external hard drives and tape drives, with storage capacities into the GBs.
Transmission Media
Transmission media connecting network elements can be divided into two classes, guided and unguided.
Guided media are characterized by physical connections between machines, as in fiber optic connections, twisted pair copper wire connections, and coaxial cable connections.
Unguided media include wireless, IR, and satellite links and result in new security challenges since signals can be intercepted by unauthorized parties.
Security Design
Physical security, the prevention of unauthorized access to actual equipment, transmission lines, and data is particularly challenging with wireless transmissions and the plethora of small data storage devices that can be easily connected to
the network via workstations.
The basis for the design of security into a network and its components comes from security policies and a strong understanding of the network resources and data that is being secured.
Security zones and security topologies provide order with respect to the wide range of data availability and security concerns, including Internet, DMZ, intranet, and extranet functionality.
The commonest topology when connecting an internal network to the Internet involves a set of two firewalls, with a DMZ area between them and no direct connections allowed across both firewalls.
