CCNA Network Infrastructure and Connectivity Practice Question
A network engineer notices that the router interface GigabitEthernet0/1 is in an 'administratively down' state in the output of the show ip interface brief command, preventing connectivity to the subnet connected to that interface. What is the most likely cause?
⚠ Common exam trap
Cisco often tests the distinction between 'administratively down' (caused by the 'shutdown' command) and 'down/down' (caused by a physical layer issue like a disconnected cable), leading candidates to confuse the two states.
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 shutdown command is configured on the interface.
The 'administratively down' state in the output of 'show ip interface brief' indicates that the interface has been manually disabled using the 'shutdown' command. This is a Layer 1/2 administrative state, not a protocol or connectivity issue. To bring the interface up, the 'no shutdown' command must be applied in interface configuration mode.
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 interface does not have an IP address assigned.
Why it's wrong here
A missing IP address does not affect the administrative state; the interface would typically show 'up/up' or 'up/down' depending on Layer 1/2, but never 'administratively down'. IP addressing is a Layer 3 parameter that only impacts routing and connectivity, whereas the administrative state is controlled at the interface configuration level by the shutdown command. Without an IP address, the interface remains administratively up and the status reflects the physical link condition. Therefore, the absence of an IP address cannot produce the 'administratively down' status.
- ✓
The shutdown command is configured on the interface.
Why this is correct
The 'administratively down' status is only displayed when the interface has been explicitly disabled using the shutdown command in configuration mode. This command sets a software flag that prevents the interface from forwarding any traffic and forces the line status to 'administratively down' regardless of the physical connection. It is a direct, intentional administrative action, and the interface will remain in this state until the no shutdown command is issued. Thus, the shutdown command is the definitive cause for this status.
- ✗
The interface is configured with an incorrect subnet mask.
Why it's wrong here
An incorrect subnet mask might cause IP communication failures but would not prevent the interface from being administratively up; the status would remain 'up/up'. The subnet mask is used by the router to determine network boundaries and routing decisions at Layer 3, and it has no bearing on the operational state of the physical interface. Even with a misconfigured mask, the interface hardware is enabled and will report 'up/up' if the link is active, as the administrative state is independent of IP parameters.
- ✗
An access list is blocking traffic on the interface.
Why it's wrong here
Access lists filter packets but do not alter interface administrative or operational state; the interface would still appear 'up/up' in the output. An ACL is applied to the interface to control which traffic is permitted or denied, functioning at Layer 3 or Layer 4, but it does not change the electrical or logical state of the interface itself. The interface remains administratively up and the line protocol will reflect the physical connection, so an ACL blocking traffic would not cause an 'administratively down' status. The only way to produce this status is via the shutdown command.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓The shutdown command is configured on the interface.Correct answer▾
Why this is correct
The 'administratively down' status is only displayed when the interface has been explicitly disabled using the shutdown command in configuration mode. This command sets a software flag that prevents the interface from forwarding any traffic and forces the line status to 'administratively down' regardless of the physical connection. It is a direct, intentional administrative action, and the interface will remain in this state until the no shutdown command is issued. Thus, the shutdown command is the definitive cause for this status.
✗The interface does not have an IP address assigned.Wrong answer — click to see why▾
Why this is wrong here
Candidates often confuse the lack of an IP address with a non-functional interface, believing it will be shown as down.
✗The interface is configured with an incorrect subnet mask.Wrong answer — click to see why▾
Why this is wrong here
Students may think any IP misconfiguration could bring the interface down, but only the shutdown command causes 'administratively down'.
✗An access list is blocking traffic on the interface.Wrong answer — click to see why▾
Why this is wrong here
Because an ACL can stop traffic, candidates sometimes assume it would be reflected as a down state, but interface status is independent of ACLs.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Visual reference
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Related to this question
Learn chapter
ARP — Address Resolution Protocol
Key term
Router
A router is a networking device that connects different networks together and directs data traffic between them by choosing the best path for data to travel.
Key term
Subnet
A subnet is a logical subdivision of an IP network, created by partitioning a larger network address space using subnet masks.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 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 200-301 exam.