200-901 Application Deployment and Security Practice Question
A developer runs the command: docker run -d -p 8080:80 --name web nginx. Which of the following best describes what happens?
⚠ Common exam trap
Many candidates confuse the order of the port mapping — candidates often assume `-p 8080:80` means container 8080 to host 80, but Docker always uses host:container order.
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
✓
The container runs in detached mode, and host port 8080 is mapped to container port 80.
The `-d` flag runs the container in detached mode (in the background), and the `-p 8080:80` flag publishes host port 8080 to container port 80. The syntax for `-p` is always `hostPort:containerPort`, so traffic hitting the host on 8080 is forwarded to port 80 inside the nginx container. The `--name web` simply assigns a friendly name to the container.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The container runs in interactive mode, and port 8080 is exposed but not published.
Why it's wrong here
Interactive mode requires -it, which is absent, and -p publishes the port rather than merely exposing it. Exposing without publishing applies to -p omitted or --expose, used when containers communicate only over a user-defined network.
- ✗
The container is removed after stopping, and port mapping is automatic.
Why it's wrong here
The `--rm` flag, absent here, is what deletes a container on exit; `-d` only detaches it, so the container persists after stopping. Port mapping is never automatic — `-p 8080:80` explicitly binds host port 8080 to container port 80. The option would fit a run using `--rm` with published ports.
- ✗
The container runs in the foreground, and port 80 on the host is mapped to port 8080 in the container.
Why it's wrong here
The -d flag detaches the container, so it runs in the background, not the foreground, and the mapping is host 8080 to container 80, not the reverse. Foreground execution occurs without -d, which is useful when watching live container output.
- ✓
The container runs in detached mode, and host port 8080 is mapped to container port 80.
Why this is correct
The -d flag detaches the container, returning the terminal immediately. The -p 8080:80 flag publishes host port 8080 and forwards it to container port 80, where nginx listens. Traffic to the host's 8080 reaches nginx inside the container.
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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 Cisco exam blueprint
This 200-901 practice question is part of Courseiva's free Cisco 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 200-901 exam.