Ways to ensure the voice network security are many. In this article we will se the first of them that must be configured in every serious network. Implementing Auxiliary VLANs will make VoIP Networks more secure using separated VLANS for data traffic and voice.
Voice and data traffic will be transferred in the same way across the same cable and same switch by default. That means that calls and all other network traffic will be transferred in the same time in the same way and every user on the network will be able to see that data using some network sniffing tool like Wireshark. This default network setting may be used to capture call packets that are crossing the network and attacker can reproduce the call in .mp3 or some other sound format. We need to separate voice network from data network completely in order to make impossible to sniff call packets from user computer.