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CCOA Technology Essentials Practice Question

In a cloud environment, you are configuring a Security Group for an EC2 instance. To allow only incoming web traffic over HTTPS from a specific subnet, which configuration is most secure?

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

Protocol: TCP, Port: 443, Source: 10.0.1.0/24

The principle of least privilege dictates specifying the exact port and source CIDR block rather than using broad '0.0.0.0/0' entries.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Protocol: TCP, Port: 443, Source: 10.0.1.0/24

    Why this is correct

    This restricts traffic to the necessary port and limits access to the specific subnet.

  • Protocol: UDP, Port: 443, Source: 10.0.1.0/24

    Why it's wrong here

    HTTPS traffic uses TCP, not UDP.

  • Protocol: TCP, Port: 80, Source: 10.0.1.0/24

    Why it's wrong here

    Port 80 is for HTTP, not HTTPS, and does not provide encrypted traffic.

  • Protocol: All Traffic, Port: All, Source: 0.0.0.0/0

    Why it's wrong here

    This opens the instance to all traffic from the internet, which is a significant security risk.

Visual reference

192.168.1.0 /24 256 addresses (254 usable) 192.168.1.0 /25 Subnet A 128 addr (126 usable) 192.168.1.128 /25 Subnet B 128 addr (126 usable) Borrowing 1 bit from host portion creates 2 subnets (/25)

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JA

Written and reviewed by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

Last reviewed August 2026 · checked against the official ISACA exam blueprint

This CCOA practice question is part of Courseiva's free ISACA 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 CCOA exam.