20+ practice questions focused on TCP & UDP Ports — one of the most tested topics on the CompTIA A+ Core 1 220-1201 exam. Each question includes a detailed explanation so you learn why the right answer is correct.
Start TCP & UDP Ports PracticeA small office reports that internal users can access the internet but cannot resolve domain names to IP addresses. The DNS server is configured correctly. Which port should be checked on the firewall?
Explanation: DNS uses port 53 for both TCP and UDP. If port 53 is blocked, DNS queries will fail, causing name resolution issues. Port 80 is for HTTP, port 443 for HTTPS, and port 67 for DHCP. Blocking port 53 prevents DNS resolution while allowing other traffic.
A company deploys a new internal application that uses a custom TCP port. The application fails to connect from client workstations. A technician verifies that the server is running and the firewall allows outbound traffic. Which step should the technician take next to identify the port issue?
Explanation: To identify the port issue, the technician should use netstat to check if the server is listening on the expected port. Telnet to the port can test connectivity, but netstat shows listening services. Ping tests ICMP, not TCP. DNS lookup resolves names, not ports. Netstat is the correct tool to verify port availability.
A technician is troubleshooting a VoIP phone that cannot register with the SIP server. The phone has a valid IP address and can ping the server. Which port should be verified as open for SIP traffic?
Explanation: SIP (Session Initiation Protocol) typically uses port 5060 for unencrypted traffic and port 5061 for encrypted traffic. Port 80 is for HTTP, port 443 for HTTPS, and port 1720 for H.323. If port 5060 is blocked, SIP registration will fail.
A user cannot connect to a remote server using RDP. The network team confirms that the firewall allows outbound traffic on all ports. Which port is typically used for RDP and should be verified on the server side?
Explanation: RDP (Remote Desktop Protocol) uses port 3389 by default. Port 22 is for SSH, port 23 for Telnet, and port 5900 for VNC. If the server's firewall is not allowing inbound traffic on port 3389, the RDP connection will fail.
A technician is configuring a network monitoring tool that uses SNMP to query network devices. Which two ports should be allowed for SNMP communication?
Explanation: SNMP uses port 161 for queries (GET/SET) and port 162 for traps (notifications). Port 161 is used by the agent to receive requests, and port 162 is used by the manager to receive traps. Ports 22 and 23 are for SSH and Telnet, 80 and 443 for web, 67 and 68 for DHCP.
+15 more TCP & UDP Ports questions available
Practice all TCP & UDP Ports questions1. Baseline your knowledge
Start with 10 questions to gauge your current understanding of TCP & UDP Ports. This tells you whether you need a concept refresher or just practice.
2. Review every explanation
For each question — right or wrong — read the full explanation. Understanding why an answer is correct is more valuable than knowing the answer itself.
3. Focus on exam traps
TCP & UDP Ports questions on the 220-1201 frequently use trap wording. Look for subtle differences in answers that test your precision, not just general knowledge.
4. Reach 80% consistently
Do repeated sessions until you score 80%+ three times in a row. Then move to mixed-mode practice to test cross-topic recall under realistic conditions.
The exact number varies per candidate. TCP & UDP Ports is tested as part of the CompTIA A+ Core 1 220-1201 blueprint. Practicing with targeted TCP & UDP Ports questions ensures you can handle any format or difficulty that appears.
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Difficulty is subjective, but TCP & UDP Ports is a high-priority exam concept tested in multiple ways — direct recall, scenario analysis, and command-output interpretation. Consistent practice is the best way to build confidence.
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