Internet Protocol Security (IPSec) is a standard-based protocol that provides the highest level of VPN security. IPSec can encrypt virtually everything above the networking layer. It is used for VPN connections that use the L2TP protocol. It secures both data and password. IPSec cannot be used with Point-to-Point Tunneling Protocol (PPTP). Answer option B is incorrect. The Internet Protocol (IP) is a protocol used for communicating data across a packet-switched inter-network using the Internet Protocol Suite, also referred to as TCP/IP. IP is the primary protocol in the Internet Layer of the Internet Protocol Suite and has the task of delivering distinguished protocol datagrams (packets) from the source host to the destination host solely based on their addresses. For this purpose, the Internet Protocol defines addressing methods and structures for datagram encapsulation. The first major version of addressing structure, now referred to as Internet Protocol Version 4 (IPv4), is still the dominant protocol of the Internet, although the successor, Internet Protocol Version 6 (IPv6), is being deployed actively worldwide. Answer option C is incorrect. Point-to-Point Protocol (PPP) is a remote access protocol commonly used to connect to the Internet. It supports compression and encryption and can be used to connect to a variety of networks. It can connect to a network running on the IPX, TCP/IP, or NetBEUI protocol. It supports multi-protocol and dynamic IP assignments. It is the default protocol for the Microsoft Dial-Up adapter. Answer option D is incorrect. Layer 2 Tunneling Protocol (L2TP) is a more secure version of Point-to-Point Tunneling Protocol (PPTP). It provides tunneling, address assignment, and authentication. It allows the transfer of Point-to-Point Protocol (PPP) traffic between different networks. L2TP combines with IPSec to provide tunneling and security for Internet Protocol (IP), Internetwork Packet Exchange (IPX), and other protocol packets across IP networks.

An automatic fire alarm system is designed for detecting the unwanted presence of fire by monitoring environmental changes associated with combustion. In general, a fire alarm system is classified as either automatically actuated, manually actuated, or both. Automatic fire alarm systems are intended to notify the building occupants to evacuate in the event of a fire or other emergency, to report the event to an off-premises location in order to summon emergency services, and to prepare the structure and associated systems to control the spread of fire and smoke. Answer option B is incorrect. A fire suppression system is used in conjunction with smoke detectors and fire alarm systems to improve and increase public safety. Answer option D is incorrect. Gaseous fire suppression is a term to describe the use of inert gases and chemical agents to extinguish a fire. Answer option A is incorrect. A fire sprinkler is the part of a fire sprinkler system that discharges water when the effects of a fire have been detected, such as when a predetermined temperature has been reached.

Explanation

Network reconnaissance
Explanation:
Network reconnaissance is typically carried out by a remote attacker attempting to gain information or access to a network on which it is not authorized or allowed. Network reconnaissance is increasingly used to exploit network standards and automated communication methods. The aim is to determine what types of computers are present, along with additional information about those computers such as the type and version of the operating system. This information can be analyzed for known or recently discovered vulnerabilities that can be exploited to gain access to secure networks and computers. Network reconnaissance is possibly one of the most common applications of passive data analysis. Early generation techniques, such as TCP/IP passive fingerprinting, have accuracy issues that tended to make it ineffective. Today, numerous tools exist to make reconnaissance easier and more effective.

In a brute force attack, an attacker uses software that tries a large number of key combinations in order to get a password. To prevent such attacks, users should create passwords that are more difficult to guess, i.e., by using a minimum of six characters, alphanumeric combinations, and lower-upper case combinations. Answer option D is incorrect. Smurf is an attack that generates significant computer network traffic on a victim network. This is a type of denial-of-service attack that floods a target system via spoofed broadcast ping messages. In such attacks, a perpetrator sends a large amount of ICMP echo request (ping) traffic to IP broadcast addresses, all of which have a spoofed source IP address of the intended victim. If the routing device delivering traffic to those broadcast addresses delivers the IP broadcast to all hosts, most hosts on that IP network will take the ICMP echo request and reply to it with an echo reply, which multiplies the traffic by the number of hosts responding. Answer option A is incorrect. Buffer overflow is a condition in which an application receives more data than it is configured to accept. It helps an attacker not only to execute a malicious code on the target system but also to install backdoors on the target system for further attacks. All buffer overflow attacks are due to only sloppy programming or poor memory management by the application developers. The main types of buffer overflows are: Stack overflow Format string overflow Heap overflow Integer overflow Answer option C is incorrect. A zero-day attack, also known as zero-hour attack, is a computer threat that tries to exploit computer application vulnerabilities which are unknown to others, undisclosed to the software vendor, or for which no security fix is available. Zero-day exploits (actual code that can use a security hole to carry out an attack) are used or shared by attackers before the software vendor knows about the mvulnerability. User awareness training is the most effective technique to mitigate such attacks.