Market researchers at the Radicati Group are even more optimistic when indicating that the number of worldwide corporate telephone lines that use VoIP will leap from 4 percent to 44 percent by 2008. With VoIP companies claiming they can cut 80 percent off the cost of the PBX and 90 percent off the maintenance costs, financial advantages are the main market drivers of internet telephony. Small, medium and large companies benefit significantly when using the less expensive alternative to traditional telephone lines. Additionally, the new technology comes with business-grade telephony features such as auto-attendant, voicemail, conferencing, call supervision, call forwarding, and more. Voice over IP gives companies the ability to consolidate telephony and networking infrastructures within the enterprise. Fixed-price internet access essentially means that overseas telephone calls are not charged extra. However, this also means that networks are open to the same kinds of attacks. Hackers could clandestinely position “zombies” in computer networks and use sniffer technology to eavesdrop on secret telephone conversations. “Voice Over Misconfigured Internet Telephones”, a program enabling intruders to access a local VoIP network and listen in to voice conversation, is already available for free on the World Wide Web. Integrating voice with e-mail and contact-management applications may also lead to unnerving consequences like “spam over internet telephony” (spit). At any rate, administrators better get ready for new challenges caused by VoIP, including the eventual threat of worms and viruses which few enterprise networks are equipped to handle today. In private and business environments alike, IP-based technologies are almost everywhere. Companies rely on Web access for their email, e-commerce, and marketing efforts, to name just a few applications. More and more, companies are installing VoIP systems to minimise telecommunications costs. But IP is not without negative side effects. First, companies need to provide enough bandwidth to ensure the flow of data and network processes. Second, IT departments are facing additional upkeep and maintenance issues when assigning static IP addresses to multiple devices, for example. And last but definitely not least, there are firewall and security issues that must be addressed to ensure the integrity of corporate data and the network.