Secure voice over Internet Protocol (voIP) using virtual private networks (VPN) and Internet Protocol Security (IPSec)

The transmission of voice information over the Internet Protocol (VoIP) offers many security challenges. After identification of the security risks, it becomes clear that most of the vulnerabilities occur in the way that voice information is handled in the IP layer [1]. This study proposes a solution using dedicated VPN-based local area firewalls. These firewalls provide more security than a border router by making the voice information less susceptible to attacks from an insider to the network. Plus, they can easily and reliably handle and protect several types of clients in small office environments, control access restricting traffic coming into the inside network and encrypt IP voice packets using IPSec tunneling before the voice packets reach the access switch.