How should I use these TCP & UDP Ports practice questions?

Read each scenario carefully and choose your answer before revealing the explanation. Then check why your choice was right or wrong. Repeat until the reasoning feels automatic.

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220-1201 · topic practice

TCP & UDP Ports practice questions

Practise identifying common TCP and UDP port numbers and their associated services as required for the 220-1201 exam.

Courseiva uses original exam-style practice questions designed for learning and revision. The goal is to understand the concepts, recognise exam patterns, and improve through explanations — not memorise copied exam dumps.

Reviewed byJohnson Ajibi· MSc IT Security

20 questionsDomain: TCP & UDP Ports

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What the exam tests

What to know about TCP & UDP Ports

This topic tests your ability to identify common TCP and UDP port numbers and their associated services.

Memorizing well-known port numbers (0-1023) for key services

Distinguishing between TCP and UDP protocol usage per service

Identifying port numbers for HTTP, HTTPS, FTP, SSH, DNS, DHCP

Recognizing port numbers for email protocols: SMTP, POP3, IMAP

Why learners struggle

Why TCP & UDP Ports questions are commonly missed

Learners often confuse port numbers for similar services or forget which protocol a service uses. This leads to incorrect answers on scenario-based questions.

·Port 22 vs 23 — SSH vs Telnet
·Port 80 vs 443 — HTTP vs HTTPS
·Port 25 vs 110 vs 143 — SMTP vs POP3 vs IMAP
·Port 20/21 vs 22 — FTP vs SSH
·Port 53 — DNS uses both TCP and UDP
·Port 67/68 vs 69 — DHCP vs TFTP

Watch out for

Common TCP & UDP Ports exam traps

▸Confusing port 22 (SSH) with port 23 (Telnet)
▸Thinking DNS uses only UDP, but it also uses TCP for zone transfers
▸Mixing up port 80 (HTTP) with port 443 (HTTPS)
▸Assuming DHCP uses TCP, but it actually uses UDP

Practice set

TCP & UDP Ports questions

20 questions · select your answer, then reveal the explanation

Question 1mediummultiple choice

Read the full DNS explanation →

A 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?

Trap 1: Port 80

Port 80 is for HTTP web traffic, not DNS.

Trap 2: Port 443

Port 443 is for HTTPS, not DNS.

Trap 3: Port 67

Port 67 is used for DHCP server, not DNS.

TCP & UDP Ports practice questions

What to know about TCP & UDP Ports

Why TCP & UDP Ports questions are commonly missed

Common TCP & UDP Ports exam traps

TCP & UDP Ports questions

A 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?

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?

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?

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?

A technician is configuring a network monitoring tool that uses SNMP to query network devices. Which two ports should be allowed for SNMP communication?

A technician is configuring a new web server that must support both standard and encrypted web traffic. Which two ports should be opened in the firewall?

A technician is troubleshooting a legacy application that uses FTP for file transfers. The transfers work but are extremely slow. The network team mentions that the firewall is configured to inspect traffic on certain ports. Which port should be opened for FTP data transfer to improve performance?

A user reports that they can receive emails but cannot send any. The email client is configured with SMTP on port 25. The IT team confirms that port 25 is blocked by the ISP. Which alternative port should be used for SMTP submission?

A technician is setting up a network printer that supports both standard and secure printing. Which port should be configured for secure IPP printing?

A customer reports that they can browse the internet but cannot send or receive emails using their desktop email client. The email server is known to be working. Which port is most likely being blocked by a firewall?

A technician is troubleshooting a VoIP phone that intermittently drops calls. The phone uses SIP (Session Initiation Protocol) for signaling and RTP (Real-time Transport Protocol) for audio. Which ports are typically used by these protocols?

A customer reports that they cannot send emails from their desktop email client, but they can receive emails. The email server is running on the local network. Which port is most likely blocked on the firewall?

A technician is configuring a new web server that must support both standard HTTP and HTTPS traffic. Which two ports should be opened in the firewall?

A technician is configuring a remote desktop solution for a user who needs to access their Windows workstation from home. Which port must be forwarded on the router for RDP (Remote Desktop Protocol)?

A company's internal DNS server is not resolving hostnames for clients. The technician verifies that the DNS service is running and the firewall allows traffic on port 53. However, clients still cannot resolve names. What is the most likely issue?

A technician is setting up a network printer that supports both LPD (Line Printer Daemon) and IPP (Internet Printing Protocol). The printer must be accessible from Windows and Linux clients. Which port should be opened for IPP?

A network administrator notices that a critical database server is responding slowly. The server uses both TCP and UDP for different services. Which of the following is a characteristic of UDP that could explain performance issues under heavy load?

A user wants to securely transfer files to a remote server using a command-line tool. Which port is the default for SFTP (SSH File Transfer Protocol)?

A security audit reveals that an internal file server is listening on multiple ports, including 137, 138, 139, and 445. The auditor recommends disabling older protocols. Which port is associated with SMB over TCP/IP directly (without NetBIOS)?

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Exam traps to avoid