19 - Considerations For Networks

Abstract

This chapter reviews the security needs for a local area network (LAN). A LAN is a complex setup that has a number of unique security needs. There are two ways to detect cable taps. The first method is by physical inspection, which should be carried out regularly. The second method involves the user of a time domain reflectometer (TDR). A LAN analyzer displays every packet of data that travels around the network, along with details of the workstation from which the data originated. Every byte, from every user is displayed by the analyzer as it travels around the network. This includes passwords and any confidential data file that a user has requested. A variation on mirroring is known as duplexing, where a computer contains two hard disk controller cards and two separate hard disks. This adds a level of security. Many network operating systems have an encryption option. When this is enabled, all data sent around the network is encrypted and thus, is of no use to someone who has tapped a cable.