In this age of the Internet, there are still many reasons to be concerned with the security of modems and dialup services. Because dialup services are easy to set up and cheap to maintain, there are many that are still in operation ”some of which have been in operation for a decade or more. Likewise, even with the wide availability of local area networks and high-speed connections, there are many reasons that you might wish to set up your own modem-based network connections:
Despite these benefits, modems come with many risks. Because people routinely use modems to transmit their usernames and passwords, you should ensure that your modems and terminal servers are properly installed, behave properly, and do exactly what they should ”and nothing else. Furthermore, because dialup services can be set up with a simple analog phone line or even a cell phone, they can be enabled by an individual without the knowledge or the authorization of an organization's management. And because Unix is so good at providing dialup access, many Unix systems that are provided with a modem for fax transmission or to access remote, non-networked systems are inadvertently providing dialup access ”sometimes without the knowledge of the system's own administrator. |