312-38 Exam Dumps : Certified Network Defender (CND)

 Class K fires involve cooking oils and fats, which are highly combustible and can ignite quickly at high temperatures. To suppress a Class K fire, a specific type of extinguishing agent is required that can separate and absorb the heat elements of the fire – the fuel, oxygen, and heat necessary to start a fire. Foam extinguishers are most suitable for Class K fires because they use a substance that turns oils into foam, effectively smothering the fire and preventing re-ignition. Water should not be used on Class K fires as it can cause the oil to splatter and spread the fire. Carbon dioxide and dry chemical extinguishers are also not recommended for Class K fires as they do not adequately remove the heat from the fire.

References: The information provided is based on standard fire safety guidelines and classifications for fire types, particularly for Class K fires involving cooking media such as oils and fats12.

 A TCP null scan attempt is a technique used in network scanning where the TCP packet sent has no flags set. This type of scan can sometimes penetrate through routers and firewalls that filter incoming packets based on certain flags because the absence of flags can prevent the packet from being filtered out. The TCP null scan is particularly useful for identifying open ports on a target system. If a port is open, the target system will not respond to the null scan, but if the port is closed, the system will send a TCP RST packet in response. This scanning method is not supported by Windows because Windows systems typically respond with a RST packet regardless of whether the port is open or closed, making it ineffective for distinguishing between the two states on those systems.

References: The TCP null scan’s ability to bypass certain types of filters and its behavior in response to open and closed ports are documented in various network security resources, including the Nmap documentation and other network security analysis articles12. These sources confirm the effectiveness of TCP null scans in penetrating through filters set up by routers and firewalls and their unsupported status on Windows systems.

 A stateful multilayer inspection firewall operates across multiple layers of the OSI model, specifically the Network, Session, and Application layers. It combines the features of packet filtering, circuit-level gateway, and application-level gateway firewalls. This type of firewall inspects the state and context of network traffic, ensuring that all packets are part of a known and valid session. It can make decisions based on the connection state as well as the contents of the traffic, providing a thorough inspection across these layers.

References: The information is consistent with the characteristics of stateful multilayer inspection firewalls as described in various sources, which confirm that they work across the Network, Session, and Application layers of the OSI model1234.