I. Explain how it is a widely held view that these unsecured, dial-up connection points represent a substantial exposure to attack.
II. Comprehend that an attacker who suspects that an organization has dial-up lines can use a device called a war dialer to locate the connection points.
III. Illustrate how a war dialer is an automatic phone-dialing program that dials every number in a configured range and checks to see if a person, answering machine, or modem picks up.
IV. Discuss how some technologies, such as RADIUS, Diameter, TACACS, and CHAP password systems, have improved the authentication and apply strong encryption.