firewalls examine every incoming packet header and can selectively filter packets based on header information such as destination address, source address, packet type, and other key information.
A. Packet filtering
B. Circuit gateways
C. Application gateways
D. MAC layer firewalls

Match the feature to the network architecture. expensive to set up useful for a small organization easy to track files has a central server inexpensive to set up difficult to track files useful for a large organization does not have a central server client- server network peer-to-peer network