Voice over Internet protocol (VoIP), is a modern method of communication. The field of "IP Telephony" is growing more and more popular today. Voice over Internet Protocol (VoIP) is the term used to describe the transmission of voice messages over packetswitched IP networks. One of the most recent forms of communication is VoIP. VoIP presents opportunities as well as security challenges, as is the case with the majority of modern technology. In contrast to the traditional circuit-based telephony, it features a distinctive architecture. VoIP is hence vulnerable to a variety of security threats