easyMultiple Choice
220-1201 Practice Question: A customer complains that their web browser…
A customer complains that their web browser cannot load any HTTPS websites, but HTTP sites work fine. The firewall is configured to allow common ports. Which port is most likely being blocked?
⚠ Common exam trap
In CompTIA A+ 220-1201, a common trap is that many candidates assume 'common ports' includes HTTPS (port 443) by default, but the CompTIA objectives expect candidates to know that port 443 must be explicitly allowed for HTTPS. The symptom of HTTP working but HTTPS failing is a classic indicator of a blocked port 443.
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
✓
443
HTTPS uses TCP port 443 for encrypted communication via TLS/SSL. If HTTP (port 80) works but HTTPS fails, the firewall is likely blocking outbound or inbound traffic on port 443, even though it allows common ports. This prevents the browser from establishing the secure connection required for HTTPS websites.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
80
Why it's wrong here
Port 80 is the standard port for Hypertext Transfer Protocol (HTTP), which handles unencrypted web traffic. If a customer can load *some* web pages, particularly those without "https://" in their URL, then port 80 is likely open and functioning correctly on their network or device. Therefore, blocking port 80 would prevent *all* standard web browsing, not just specific secure sites, making it an unlikely cause for the described symptom.
- ✓
443
Why this is correct
Port 443 is the standard port for Hypertext Transfer Protocol Secure (HTTPS), which encrypts web traffic using SSL/TLS for secure communication. If a customer's web browser cannot load certain websites, especially those requiring secure connections (indicated by "https://"), but can still access unencrypted HTTP sites, then a block or misconfiguration on port 443 is the most probable cause. This scenario specifically points to an issue with secure communication, leaving unencrypted traffic unaffected.
- ✗
22
Why it's wrong here
Port 22 is exclusively used for Secure Shell (SSH), a cryptographic network protocol for operating network services securely over an unsecured network. It is primarily employed for secure remote command-line access, file transfers (SFTP), and tunneling, not for standard web browsing activities. Blocking or misconfiguring port 22 would only impact remote administration capabilities, having no direct effect on a web browser's ability to load websites.
- ✗
53
Why it's wrong here
Port 53 is dedicated to the Domain Name System (DNS), which translates human-readable domain names (like example.com) into numerical IP addresses that computers use to identify each other. While essential for initiating web connections, a complete block on port 53 would prevent *any* website from loading by its domain name, not just secure ones. If some sites load, DNS resolution is generally working, indicating the issue lies elsewhere, specifically with the type of traffic.
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Key term
Firewall
A firewall is a network security system that monitors and controls incoming and outgoing traffic based on predetermined security rules to protect trusted internal networks from untrusted external networks.
Key term
TCP
TCP (Transmission Control Protocol) is a core internet protocol that ensures data is sent reliably and in order between devices over a network.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.