ISC2 CC Network Security Practice Question
Which of the following ports is used by HTTPS?
⚠ Common exam trap
Many candidates confuse port 80 (HTTP) with port 443 (HTTPS); candidates who memorize only 'web = 80' pick A without noticing the 'S' in HTTPS.
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 (Hypertext Transfer Protocol Secure) operates over TCP port 443 by default, using TLS to encrypt HTTP traffic between client and server. This is the IANA-assigned well-known port for HTTPS, so any browser request to https:// implicitly targets port 443 unless overridden. Port 80 is the counterpart for unencrypted HTTP, which is why the two are so often confused.
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 carries unencrypted HTTP; HTTPS uses 443 with TLS. Port 80 is the right answer when a question asks about plain web traffic or a URL beginning http://, but it provides no transport encryption for the session.
- ✗
21
Why it's wrong here
Port 21 carries FTP control commands, not HTTPS traffic, so it cannot satisfy a requirement for encrypted web access on the standard TLS port. It is tempting because 21 is a well-known, memorised port number, and it would be the correct choice if the question instead asked which port FTP uses for its control connection.
- ✗
25
Why it's wrong here
Port 25 carries SMTP for mail relay, so it cannot serve HTTPS traffic. It is tempting because 25 is a well-known assigned port, but that assignment belongs to email transport; HTTPS listens on TCP 443, which the scenario requires.
- ✓
443
Why this is correct
HTTPS uses TCP port 443 by default, carrying HTTP traffic encrypted with TLS. Port 80 serves plain HTTP, while 22 and 3389 handle SSH and RDP respectively. Browsers and servers therefore negotiate secure web sessions on 443 unless an administrator configures a non-standard port.
Go deeper
Related to this question
Learn chapter
Secure Network Architecture and Design
Key term
TCP
TCP is a connection-oriented transport layer protocol that ensures reliable, ordered, and error-checked delivery of data between applications over IP networks.
Key term
Hypertext Transfer Protocol Secure
Hypertext Transfer Protocol Secure, or HTTPS, is the secure version of HTTP that encrypts data between a web browser and a website using SSL/TLS to protect sensitive information like passwords and credit card numbers.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official ISC2 exam blueprint
This CC practice question is part of Courseiva's free ISC2 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 CC exam.