Network forensic is a new growing approach to a network security. Digital forensic applies the forensic procedure to electronic or digital evidence. This digital forensic process involves systematically collecting and analyzing digital information for use as evidence in court. Network forensics is a branch of digital forensics that focuses on the monitoring and analysis of network traffic. Network forensics is the process of gathering and examining raw data of network and systematically tracking and monitoring traffic of network to make sure of how an attack took place. Network forensic will help in identifying unauthorized access to computer systems and networks, and searches for evidence if it will happen. In this paper, we are focusing on network forensics, the steps to perform network forensics, various network forensic tools, comparison chart, and emerging area of network forensics.