Final answer:
A packet-filtering firewall is the type of firewall that examines the header of every packet to determine its authorization to reach its destination, operating at the network layer to control access based on IP addresses, ports, and protocols.
Step-by-step explanation:
The type of firewall being described in the question is known as a packet-filtering firewall. This kind of firewall is responsible for examining the header of every packet of data it receives to make an informed decision about whether that type of packet is authorized to continue to its destination. The main function of a packet-filtering firewall is to control network access by monitoring outgoing and incoming packets and either allowing them to pass or halting them based on the applied rule set.
A packet-filtering firewall works at the network layer of the OSI model and can make decisions based on source and destination IP addresses, ports, or protocols used in the header of the packets. This is a relatively simple type of firewall and does not inspect the packet contents but provides basic network security by blocking potentially harmful packets based on predefined rules.