CompTIA Networking Practice Test

Question 1

Which OSI model layer is responsible for logical addressing and routing packets between networks?

Accepted Answer

Layer 3 — Network

Answer

Layer 3 (Network Layer) handles logical addressing (IP addresses) and routing, determining the best path for packets to travel between different networks. Routers operate at this layer. Layer 2 handles physical addressing (MAC), Layer 4 handles transport (TCP/UDP), and Layer 1 handles physical transmission.

Question 2

A computer has the IP address 192.168.1.45 with a subnet mask of 255.255.255.0. What is the network address?

Accepted Answer

192.168.1.0

Answer

The network address is found by performing a bitwise AND between the IP address and subnet mask. 192.168.1.45 AND 255.255.255.0 = 192.168.1.0. The /24 subnet (255.255.255.0) means the first 24 bits identify the network, leaving the last octet (0-255) for host addresses.

Question 3

What protocol is used to automatically assign IP addresses to devices on a network?

Accepted Answer

DHCP

Answer

DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses, subnet masks, default gateways, and DNS server addresses to network devices. Without DHCP, each device would need to be manually configured with a static IP address. DHCP uses UDP ports 67 (server) and 68 (client).

Question 4

What is the difference between TCP and UDP?

Accepted Answer

TCP is reliable and connection-oriented; UDP is faster but connectionless with no delivery guarantee

Answer

TCP (Transmission Control Protocol) is connection-oriented and provides reliable, ordered, error-checked delivery through acknowledgments and retransmission. UDP (User Datagram Protocol) is connectionless and provides faster but unreliable delivery with no acknowledgments. TCP is used for HTTP/HTTPS, email, FTP. UDP is used for DNS, video streaming, VoIP.

Question 5

What is the primary function of a DNS server?

Accepted Answer

Translate domain names to IP addresses

Answer

DNS (Domain Name System) translates human-readable domain names (like www.google.com) into IP addresses (like 142.250.80.46) that computers use to communicate. Without DNS, users would need to memorize IP addresses to visit websites. DNS uses UDP/TCP port 53.

CompTIA Practice Test

CompTIA Practice Test

CompTIA Networking Practice Test