Final answer:
To authenticate a VoIP system, creation of a user account for each individual user is required. A firewall is also essential for securing the VoIP system, but a router and antivirus software are not directly involved in the authentication process.
Step-by-step explanation:
To authenticate a VoIP system that needs access to the internet, you will generally need to create a user account for each person who will be using the VoIP service. This user account will need to be configured within the VoIP system's servers and devices. However, to ensure secure communication, a firewall is also essential. A firewall monitors and controls incoming and outgoing network traffic based on predetermined security rules, protecting the network against unauthorized access and potential cyber threats. While a router is necessary for directing data packets between the internet and local devices, it does not authenticate users. Similarly, antivirus software protects against malware but does not play a direct role in the authentication process of VoIP systems.