CertiGuide to Security+  9  Chapter 3:  Infrastructure Security (Domain 3.0; 20%)       9  3.1  Devices

3.1.4  Wireless 1 2 3.1.6  RAS (Remote Access Server)

Modems allow users to use telephone lines to call in to a network, computer, or fax machine from a remote location. Most modems today use the V.90 standard, theoretically communicating at up to 56kb/sec, although they are limited to 53kb/sec (kilobits per second) by the telephone network. Older modems may communicate at 33.6kb/sec, 28.8kb/sec, 14.4kb/sec, or even 9600bits/sec or slower. Other devices that connect a home PC with a cable Internet connection or DSL connection are often referred to as “cable modems” or “DSL modems”, but they more closely resemble routers than modems in the traditional sense. And these have issues as well beyond what you may typically think ²⁷⁵ Employees working at home, providing after-hours support, exchanging data among business partners, sending and receiving faxes, and accessing the network from off-site company locations that do not have permanent network connections, use modems in corporate settings most commonly for telecommuting.

Modems can be internal (on cards which plug into a PC or laptop) or external (separate boxes outside the computer). External modems typically connect to computers via serial or USB connections.

In the case of a serial connection, and probably also for USB, a “tap” can be inserted between the computer and modem, so that communications can be intercepted and recorded, compromising data privacy. For that matter, an appropriate device between computer and modem could even take over the conversation.

3.1.4  Wireless 1 2 3.1.6  RAS (Remote Access Server)