COMPTIA / TOPIC PRACTICE CompTIA A+ Networking Practice Questions
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Build foundational networking skills with practice questions on TCP/IP, ports, protocols, Wi-Fi standards, and connectivity troubleshooting for 2026.

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CompTIA A+ Networking Practice Questions

Build foundational networking skills with practice questions on TCP/IP, ports, protocols, Wi-Fi standards, and connectivity troubleshooting for 2026.

~20%of Core 1 Exam

15+Key Ports

8CLI Tools

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Study schedules, salary ranges, and optional materials budgets on this page are planning examples. They are not verified salary surveys, current price quotes, or guarantees of passing or employment. Check the current regional exam price before booking. CompTIA does not publish pass rates or individual question weights. Practice percentages are review aids, not pass predictors.

Provider references checked September 8, 2026: Current certifications · CEU requirements · Renewal fees.

Networking on the CompTIA A+ Exam

Networking fundamentals form a critical part of the CompTIA A+ certification, representing approximately 23% of Core 1 exam. As an IT support technician, you will constantly interact with network infrastructure—configuring IP addresses, troubleshooting connectivity issues, setting up wireless networks, and understanding how data flows across LANs and WANs.

The A+ networking domain focuses on practical, entry-level skills. Unlike the Network+ certification which dives deep into network design and implementation, the A+ expects you to understand how networks work from an end-user support perspective. You need to configure network settings on client machines, identify when a problem is network-related versus hardware or software, and use command-line tools to diagnose issues.

Exam questions in this domain are heavily scenario-based. You might be presented with a user unable to access the internet, a printer that cannot be found on the network, or a VPN connection that keeps dropping. Your ability to systematically identify the layer of the problem (physical, data link, network, transport, or application) will determine your success.

Key Networking Concepts

🌐 TCP/IP Model

Four layers: Network Interface, Internet, Transport, and Application. Understand how data is encapsulated at each layer and the key protocols operating at each level.

🔢 IP Addressing

IPv4 addressing, subnet masks, CIDR notation, private address ranges (10.x, 172.16-31.x, 192.168.x), APIPA (169.254.x.x), and IPv6 basics including link-local addresses.

📡 Wireless Standards

Wi-Fi 5 (802.11ac), Wi-Fi 6 (802.11ax), Wi-Fi 6E, frequency bands (2.4 GHz vs 5 GHz vs 6 GHz), channel configuration, and wireless security protocols (WPA2, WPA3).

🔌 Network Devices

Routers, managed and unmanaged switches, wireless access points, firewalls, modems, network attached storage (NAS), and power over Ethernet (PoE) injectors.

🛠️ Troubleshooting Tools

ipconfig, ping, tracert, nslookup, netstat, pathping, and net commands. Know the output format and diagnostic value of each tool.

🔒 Network Services

DNS resolution process, DHCP lease cycle (DORA), NAT/PAT, proxy servers, VPN types, and common email protocols (SMTP, POP3, IMAP).

Essential Ports and Protocols

Port	Protocol	Transport	Purpose
20/21	FTP	TCP	File transfer (data/control)
22	SSH	TCP	Secure remote access
23	Telnet	TCP	Unsecured remote access
25	SMTP	TCP	Email sending
53	DNS	TCP/UDP	Domain name resolution
67/68	DHCP	UDP	Dynamic IP assignment
80	HTTP	TCP	Web traffic (unencrypted)
110	POP3	TCP	Email retrieval
143	IMAP	TCP	Email access (synced)
443	HTTPS	TCP	Secure web traffic
445	SMB	TCP	Windows file sharing
3389	RDP	TCP	Remote desktop

Sample Networking Practice Question

Question: A user reports they cannot access any websites but can ping external IP addresses successfully. Internal network resources work fine. Which service is most likely experiencing an issue?

A) DHCP
B) DNS
C) Default gateway
D) NAT

Correct Answer: B

Explanation: The user can ping IP addresses (proving Layer 3 connectivity works) but cannot access websites by name. This indicates DNS resolution is failing. If DHCP were the issue, the user would likely have no IP or an APIPA address. If the default gateway were down, pinging external IPs would also fail. NAT issues would prevent all external communication, not just name resolution.

Network Troubleshooting Methodology

When approaching network troubleshooting on the A+ exam, follow a bottom-up approach through the TCP/IP layers:

Physical Layer: Check cable connections, link lights on NICs and switches, verify Wi-Fi is enabled, test with known-good cables
Network Layer: Run ipconfig to verify IP configuration, check for APIPA addresses (169.254.x.x indicating DHCP failure), verify subnet mask and default gateway
Connectivity: Ping localhost (127.0.0.1), ping default gateway, ping external IP (8.8.8.8), then ping a hostname to test DNS
Name Resolution: Use nslookup to test DNS directly, try alternative DNS servers, check hosts file for overrides, flush DNS cache with ipconfig /flushdns
Application Layer: Test specific services (HTTP, email), check firewall rules, verify proxy settings, clear browser cache

Study Checklist: Networking Domain

☐ Memorize all common ports (at least 15 port/protocol pairs)
☐ Explain the DHCP DORA process step by step
☐ Identify private vs public IP address ranges
☐ Use ipconfig, ping, tracert, and nslookup from memory
☐ Compare Wi-Fi standards and their maximum speeds
☐ Describe the DNS resolution process
☐ Differentiate between switches, routers, and access points
☐ Understand APIPA and what it indicates

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Before you begin

23% of exam (Core 1)

Networking represents a core competency area for CompTIA A+ certification. Focused practice here builds the foundation for exam-day confidence.

Network issues cause the majority of IT tickets. Strong networking skills make you invaluable.

What is Networking?

Networking on the CompTIA A+ exam covers the fundamentals that every IT technician needs to connect, configure, and troubleshoot network connectivity. This includes understanding TCP/IP addressing, common protocols, network hardware like routers and switches, and wireless networking standards. While the A+ exam does not go as deep as the Network+ certification, it establishes essential baseline knowledge for support roles.

Understanding Networking deeply prepares you for both certification success and practical job responsibilities. This isn't just exam content—it's career currency.

Why Networking Matters

Nearly every help desk ticket involves network connectivity in some form. Users cannot access email, printers are not responding, VPN connections fail, or websites will not load. A technician who understands networking can quickly isolate whether the problem is local (device configuration), infrastructure (switch/router), or external (ISP/internet). Strong networking fundamentals also prepare you for more advanced certifications and roles.

Key Concepts to Master

IPv4 Addressing

32-bit addresses in dotted decimal (192.168.1.1). Private ranges: 10.x.x.x, 172.16-31.x.x, 192.168.x.x. Subnet masks define network/host portions.

IPv6 Addressing

128-bit addresses in hexadecimal. Eliminates NAT requirement. Link-local addresses start with fe80::.

Dynamic Host Configuration Protocol automatically assigns IP addresses. DORA process: Discover, Offer, Request, Acknowledge.

Domain Name System resolves hostnames to IP addresses. Common record types: A (IPv4), AAAA (IPv6), MX (mail), CNAME (alias).

TCP vs UDP

TCP provides reliable, ordered delivery with handshakes. UDP is faster but connectionless. HTTP uses TCP; DNS uses UDP.

Common Ports

HTTP (80), HTTPS (443), FTP (21), SSH (22), RDP (3389), DNS (53), DHCP (67/68), SMTP (25/587).

Ethernet Standards

Cat5e (1 Gbps/100m), Cat6 (10 Gbps/55m), Cat6a (10 Gbps/100m). RJ-45 connectors standard.

Routers connect networks and route by IP. Switches forward frames by MAC within a LAN. APs provide wireless access.

Sample Question Types

1.IP addressing: Which IP address is a valid private address?
2.Port identification: A firewall is blocking a web application. Which ports should be allowed for HTTPS traffic?
3.Troubleshooting: A user cannot access the internet but can ping the default gateway. What should you check next?
4.Hardware selection: Which cable type supports 10 Gbps at 100 meters?

Common Mistakes to Avoid

✗Confusing private and public IP address ranges
✗Forgetting that DNS uses UDP for queries but TCP for zone transfers
✗Mixing up default ports for similar services (HTTP 80 vs HTTPS 443)
✗Not understanding the difference between routers and switches
✗Overlooking wireless channel overlap on 2.4 GHz (use channels 1, 6, 11)

Study Checklist

Memorize private IP address ranges and subnet masks
Know common port numbers for at least 15 services
Understand DHCP lease process and troubleshooting
Practice subnetting with CIDR notation
Learn OSI model layers and their functions
Review Ethernet cable categories and maximum distances
Understand WiFi standards and their frequencies
Know basic network troubleshooting commands (ping, tracert, nslookup, ipconfig)

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Frequently Asked Questions

What networking topics are on the CompTIA A+ exam?

The A+ exam tests TCP/IP fundamentals, common ports and protocols, network device identification (routers, switches, access points), Wi-Fi standards, IP addressing and subnetting basics, DNS, DHCP, and basic network troubleshooting using command-line tools.

What ports should I memorize for the A+ networking exam?

Key ports include: HTTP (80), HTTPS (443), FTP (20/21), SSH (22), Telnet (23), SMTP (25), DNS (53), DHCP (67/68), POP3 (110), IMAP (143), RDP (3389), SMB (445), and LDAP (389). Know both TCP and UDP assignments.

How much of the A+ exam focuses on networking?

Networking represents approximately 23% of Core 1 exam. This includes network types, devices, cables, TCP/IP addressing, and wireless standards. Additional network troubleshooting questions may appear across other domains.

Do I need to know subnetting for CompTIA A+?

Basic subnetting is tested on the A+ exam. You should understand default subnet masks for Class A, B, and C networks, CIDR notation, and be able to identify which devices are on the same subnet. Advanced subnetting calculations are more relevant for Network+.

What is the difference between TCP and UDP for the A+ exam?

TCP (Transmission Control Protocol) is connection-oriented, provides reliable delivery with acknowledgments, and uses a three-way handshake. UDP (User Datagram Protocol) is connectionless, faster but unreliable, used for streaming, DNS queries, and VoIP. Know which protocols use each.

What network troubleshooting tools are tested on A+?

You should know ipconfig/ifconfig, ping, tracert/traceroute, nslookup/dig, netstat, pathping, nbtstat, and net commands. Understand what each tool reveals and when to use it in a troubleshooting scenario.