WGU D315 NETWORK AND SECURITY
FOUNDATION ACTUAL TEST QUESTIONS
WITH COMPLETE ANSWER KEY
●● Which service automatically assigns IP addresses to network
devices?
Answer: DHCP (Dynamic Host Configuration Protocol).
●● How is a domain name resolved to an IP address?
Answer: DNS (Domain Name System) resolves website names to IP
addresses.
●● How does a switch handle an Ethernet frame for a known
destination?
Answer: It forwards the frame through the port matched in its MAC
table.
●● What technique is best for separating broadcast domains?
Answer: Routing or Layer 3 network segmentation.
●● What mechanisms does TCP use to ensure reliable delivery?
Answer: Acknowledgments, sequencing numbers, retransmissions, and
flow control.
,●● What happens if a device has an incorrect default gateway?
Answer: Traffic destined for remote networks fails to leave the local
subnet.
●● How do you select a subnet mask for a planned host count?
Answer: Choose a prefix that provides enough usable addresses for
hosts.
●● How does an IPv4 host determine a local neighbor's MAC address?
Answer: By sending an ARP (Address Resolution Protocol) request.
●● What is the first phase when troubleshooting network connectivity
loss?
Answer: Systematically verify physical connectivity, IP addressing,
gateway, and reachability.
●● What is the primary function of Layer 1 in the OSI model?
Answer: Transmitting raw bitstreams over a physical medium.
●● What is the primary unit of data at the Physical Layer?
Answer: Bits.
,●● Which OSI layer is responsible for MAC addressing and node-to-
node delivery?
Answer: Layer 2 - Data Link Layer.
●● What is the Protocol Data Unit (PDU) at Layer 2?
Answer: Frame.
●● Which OSI layer handles logical addressing and path determination?
Answer: Layer 3 - Network Layer.
●● What is the PDU at the Network Layer?
Answer: Packet.
●● Which OSI layer provides end-to-end communication and port
numbers?
Answer: Layer 4 - Transport Layer.
●● What is the PDU at the Transport Layer for TCP?
Answer: Segment.
●● What is the PDU at the Transport Layer for UDP?
Answer: Datagram.
, ●● Which OSI layer manages session establishment, maintenance, and
termination?
Answer: Layer 5 - Session Layer.
●● Which OSI layer handles data formatting, encryption, and
compression?
Answer: Layer 6 - Presentation Layer.
●● Which OSI layer provides network services directly to end-user
applications?
Answer: Layer 7 - Application Layer.
●● Name the four layers of the TCP/IP model.
Answer: Network Access, Internet, Transport, and Application.
●● Which TCP/IP layer corresponds to OSI Layers 1 and 2?
Answer: Network Access Layer.
●● Which TCP/IP layer corresponds to OSI Layer 3?
Answer: Internet Layer.
●● Which protocols operate primarily at the Internet Layer of TCP/IP?
Answer: IP, ICMP, ARP, and IPsec.
FOUNDATION ACTUAL TEST QUESTIONS
WITH COMPLETE ANSWER KEY
●● Which service automatically assigns IP addresses to network
devices?
Answer: DHCP (Dynamic Host Configuration Protocol).
●● How is a domain name resolved to an IP address?
Answer: DNS (Domain Name System) resolves website names to IP
addresses.
●● How does a switch handle an Ethernet frame for a known
destination?
Answer: It forwards the frame through the port matched in its MAC
table.
●● What technique is best for separating broadcast domains?
Answer: Routing or Layer 3 network segmentation.
●● What mechanisms does TCP use to ensure reliable delivery?
Answer: Acknowledgments, sequencing numbers, retransmissions, and
flow control.
,●● What happens if a device has an incorrect default gateway?
Answer: Traffic destined for remote networks fails to leave the local
subnet.
●● How do you select a subnet mask for a planned host count?
Answer: Choose a prefix that provides enough usable addresses for
hosts.
●● How does an IPv4 host determine a local neighbor's MAC address?
Answer: By sending an ARP (Address Resolution Protocol) request.
●● What is the first phase when troubleshooting network connectivity
loss?
Answer: Systematically verify physical connectivity, IP addressing,
gateway, and reachability.
●● What is the primary function of Layer 1 in the OSI model?
Answer: Transmitting raw bitstreams over a physical medium.
●● What is the primary unit of data at the Physical Layer?
Answer: Bits.
,●● Which OSI layer is responsible for MAC addressing and node-to-
node delivery?
Answer: Layer 2 - Data Link Layer.
●● What is the Protocol Data Unit (PDU) at Layer 2?
Answer: Frame.
●● Which OSI layer handles logical addressing and path determination?
Answer: Layer 3 - Network Layer.
●● What is the PDU at the Network Layer?
Answer: Packet.
●● Which OSI layer provides end-to-end communication and port
numbers?
Answer: Layer 4 - Transport Layer.
●● What is the PDU at the Transport Layer for TCP?
Answer: Segment.
●● What is the PDU at the Transport Layer for UDP?
Answer: Datagram.
, ●● Which OSI layer manages session establishment, maintenance, and
termination?
Answer: Layer 5 - Session Layer.
●● Which OSI layer handles data formatting, encryption, and
compression?
Answer: Layer 6 - Presentation Layer.
●● Which OSI layer provides network services directly to end-user
applications?
Answer: Layer 7 - Application Layer.
●● Name the four layers of the TCP/IP model.
Answer: Network Access, Internet, Transport, and Application.
●● Which TCP/IP layer corresponds to OSI Layers 1 and 2?
Answer: Network Access Layer.
●● Which TCP/IP layer corresponds to OSI Layer 3?
Answer: Internet Layer.
●● Which protocols operate primarily at the Internet Layer of TCP/IP?
Answer: IP, ICMP, ARP, and IPsec.
