What is the primary function of basic packet-filtering firewalls?

The primary function of basic packet-filtering firewalls is to analyze network traffic transmitted in packets. These firewalls examine the header information of packets, which includes source and destination IP addresses, port numbers, and protocols used, to determine whether to allow or block the transmission based on the established security rules. This layer of analysis enables network administrators to control traffic flows and maintain security by filtering packets based on predefined criteria.

While other options involve network security concepts, they do not accurately describe the specific function of basic packet-filtering firewalls. For instance, inspecting the content of packets for threats pertains more to deep packet inspection or advanced firewalls that can analyze payload data. Assigning IP addresses is a function more related to DHCP (Dynamic Host Configuration Protocol) rather than packet filtering. Lastly, providing a physical layout of nodes in a network is associated with network topology mapping and has no direct relation to the operation of packet-filtering firewalls.