- A
21
Why wrong: Port 21 is FTP, which is unencrypted and not secure for internet transfers.
- B
22
Port 22 is SSH, which SFTP uses for secure file transfers.
- C
20
Why wrong: Port 20 is FTP data port, used in active FTP, but still unencrypted.
- D
443
Why wrong: Port 443 is HTTPS, used for web traffic, not file transfers.
Question 246 of 1,020
220-1201 TCP & UDP Ports Practice Question
This 220-1201 practice question tests your understanding of tcp & udp ports. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A user needs to transfer files securely between two Linux servers over the internet. Which port should be allowed through the firewall for this purpose?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
22
Secure file transfer between Linux servers typically uses SCP (Secure Copy) or SFTP (SSH File Transfer Protocol), both of which operate over SSH. SSH uses TCP port 22 by default, so allowing port 22 through the firewall enables encrypted authentication and data transfer. This is the correct choice because it provides confidentiality and integrity for the file transfer over the internet.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
21
Why it's wrong here
Port 21 is FTP, which is unencrypted and not secure for internet transfers.
- ✓
22
Why this is correct
Port 22 is SSH, which SFTP uses for secure file transfers.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
20
Why it's wrong here
Port 20 is FTP data port, used in active FTP, but still unencrypted.
- ✗
443
Why it's wrong here
Port 443 is HTTPS, used for web traffic, not file transfers.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse FTP (ports 20/21) with secure file transfer, forgetting that FTP lacks encryption, or they mistakenly think HTTPS (port 443) is the standard for server-to-server file transfers, when SSH on port 22 is the correct protocol for secure Linux-to-Linux transfers.
Detailed technical explanation
How to think about this question
SSH (Secure Shell) on port 22 uses a client-server model with public-key cryptography for authentication and symmetric encryption (e.g., AES) for the session. SCP relies on the SSH protocol to copy files, while SFTP (not to be confused with FTPS) uses a single persistent connection on port 22, avoiding the separate data channel issues of FTP. In real-world scenarios, administrators often restrict port 22 to specific source IPs or use SSH key-based authentication to further harden access.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the 220-1201 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this 220-1201 question test?
TCP & UDP Ports — This question tests TCP & UDP Ports — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: 22 — Secure file transfer between Linux servers typically uses SCP (Secure Copy) or SFTP (SSH File Transfer Protocol), both of which operate over SSH. SSH uses TCP port 22 by default, so allowing port 22 through the firewall enables encrypted authentication and data transfer. This is the correct choice because it provides confidentiality and integrity for the file transfer over the internet.
What should I do if I get this 220-1201 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
This 220-1201 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1201 exam.
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