Trouble on the Line

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SYNOPSIS
Many companies are switching phone service to the Internet. That service is called Voice over Internet Protocol (VoIP), and those communications travel across computer networks, thus providing a host of advantages such as flexibility and low cost. At the same time, putting telephone communications on the Internet opens them up to new risks. To understand the risks, one must understand the network basics.

All data that moves across a network is first broken into packets that contain instructions on where data should be sent and how the packets should be put back together. The protocols that accomplish these functions are Transmission Control Protocol (TCP) and Internet Protocol (IP), together known as TCP/IP. When a device is attached to a network, it needs a numerical name given to it by a network “411” service called the Domain Name System (DNS); this is typically done automatically by a technology called the Dynamic Host Control Protocol (DHCP).

DNS is critical to VoIP communications, but it’s also difficult to avoid DNS configuration errors that introduce problems and even create potential security risks, such as “spoofing” (where an attacker mimics a server and reroutes calls).

Administrators can take full advantage of the cost savings of VoIP and overcome configuration and security challenges by using IP Address Management (IPAM) tools that automate the process of setting up VoIP devices, help allocate IP addresses to new devices efficiently, and provide security functions such as intrusion detection.