When implementing an IP telephony network, it is essential to carefully consider security; otherwise, the network will be vulnerable to attack and voice communications may suffer disruption.
Several different tools and techniques can be used to protect the IP telephony networks, and some of these are covered in this chapter.
Several different tools and techniques can help protect the network against both Layer 2 and Layer 3 threats. One such technique is DHCP snooping.
VoIP devices, such as IP phones, can use the Dynamic Host Configuration Protocol (DHCP) to obtain IP configuration parameters, such as IP address and TFTP server address. Therefore, if an attacker is able to interfere with DHCP, he might be ...