The very nature of VoIP telephone calls being transmitted over the internet means that they are vulnerable to the same threats as other online data services. The use of VoIP telephones presents five prime areas of concern regarding security and they are described as follows:

4.1 Toll Fraud

Toll fraud is an attempt by a hacker to gain unlawful remote access to a VoIP telephone system, usually through an open IP or SIP (Session Initiation Protocol) port. Successful attacks result in the hacker being able to make calls to premium numbers at the expense of the company.

A toll fraud attack could potentially leave the company with an expensive telephone bill if the attack goes undetected. There are, however, measures which can be taken to try and prevent toll fraud attacks. Password protection is the first line of defence and a strong password consisting of numerals, capitals and lowercase letters is recommended. Staff should be trained to use secure passwords and ensure that they are changed regularly. The VoIP system should always be behind a firewall and encryption of voice data is also highly recommended. …show more content…
The quality of a call can degrade significantly if IP voice packets are lost or suffer delays at any given time during a call between the VoIP users (Das, 2016). The next generation of VoIP technology is set to use IPv6 infrastructure which will ensure quality of service. IPv6 achieves this quality of service by use of classification and marking of data packets, ensuring a reliable VoIP infrastructure (Das, 2016). As VoIP grows ever more popular, the limitations of IPv4 address space will hinder its expansion. IPv6 provides a solution to this problem by allowing vastly more unique IP addresses as well as built-in encryption making it much safer than IPv4 based