Snort is an open source network intrusion prevention and detection system that operates as a network sniffer. It logs activities of the network that is matched with the predefined signatures. Signatures can be designed for a wide range of traffic, including Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and Internet Control Message Protocol (ICMP). The three main modes in which Snort can be configured are as follows: Sniffer mode: It reads the packets of the network and displays them in a continuous stream on the console. Packet logger mode: It logs the packets to the disk. Network intrusion detection mode: It is the most complex and configurable configuration, allowing Snort to analyze network traffic for matches against a user-defined rule set. Answer: C is incorrect. Macof is a tool of the dsniff tool set and used to flood the local network with random MAC addresses. It causes some switches to fail open in repeating mode, and facilitates sniffing. Answer: A is incorrect. Sourcefire is the company that owns and maintains Snort. Answer: B is incorrect. NETSH is not a network intrusion detection system. NETSH is a command line tool to configure TCP/IP settings such as the IP address, Subnet Mask, Default Gateway, DNS, WINS addresses, etc.