CCNA Network Infrastructure and Connectivity Practice Question
Network Topology
You are connected to R1. The link between R1 and R2 is down. The output of 'show interfaces gigabitEthernet0/0' on R1 shows: 'GigabitEthernet0/0 is administratively down, line protocol is down (disabled)', with IP address 203.0.113.1/30, MTU 1500, and no input/output errors. Determine the root cause and configure the necessary fix to bring the interface up and restore connectivity.
⚠ Common exam trap
Candidates often miss the 'administratively down' keyword in show interfaces output and instead look for speed/duplex mismatches; always read the interface status first.
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
✓
Enter interface configuration mode for GigabitEthernet0/0 and issue the 'no shutdown' command.
The interface status 'administratively down' means the interface was manually shut down using the 'shutdown' command. To bring it up, you must enter interface configuration mode and issue 'no shutdown', which administratively enables the interface. The other options are incorrect: setting speed to 100 Mbps or forcing full-duplex will not fix an administratively down state, and disabling keepalives is unrelated to the interface being disabled.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Enter interface configuration mode for GigabitEthernet0/0 and issue the 'no shutdown' command.
Why this is correct
The output designated for this interface shows 'GigabitEthernet0/0 is administratively down', which is the direct result of the interface being placed into the shutdown state. By entering interface configuration mode for GigabitEthernet0/0 and issuing the 'no shutdown' command, the administrator clears the administrative disable flag, allowing the interface to begin the physical layer and line protocol bring-up process. This is the only command among the choices that directly changes the administrative state from 'down' to 'up'.
- ✗
Enter interface configuration mode and issue the 'speed 100' command to match the remote interface speed.
Why it's wrong here
Setting the interface speed to 100 Mbps is a common fix for speed mismatches, but such mismatches cause symptoms like CRC errors, runts, or the interface going up/down intermittently, never an administratively down state. The 'administratively down' code means the interface is deliberately disabled in NVRAM/configuration, and altering a physical parameter like speed will not change the interface's shutdown status. You must first issue 'no shutdown' to enable the interface before any speed negotiation can take effect.
- ✗
Enter interface configuration mode and issue the 'duplex full' command to force full-duplex operation.
Why it's wrong here
Forcing full-duplex operation addresses duplex negotiation issues, which typically present as excessive CRC errors, late collisions, or high input errors—not an administratively down state. An interface that is administratively down has been manually disabled via the 'shutdown' command, so the physical layer and duplex settings are irrelevant until it is re-enabled. Moreover, on GigabitEthernet links, misconfiguring duplex to 'full' while the remote side autonegotiates could cause a mismatch, but the current state still stems from the shutdown configuration.
- ✗
Enter interface configuration mode and issue the 'no keepalive' command to disable keepalives.
Why it's wrong here
Disabling keepalives cannot repair an administratively down interface. Keepalives are periodic messages used to verify remote reachability; if keepalives are not received, the line protocol may be marked down, but the interface's administrative state remains 'up' unless explicitly shut. The 'administratively down' status in 'show interfaces' indicates the shutdown command has been applied, so the necessary intervention is 'no shutdown', not 'no keepalive'.
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.
✓Enter interface configuration mode for GigabitEthernet0/0 and issue the 'no shutdown' command.Correct answer▾
Why this is correct
The output designated for this interface shows 'GigabitEthernet0/0 is administratively down', which is the direct result of the interface being placed into the shutdown state. By entering interface configuration mode for GigabitEthernet0/0 and issuing the 'no shutdown' command, the administrator clears the administrative disable flag, allowing the interface to begin the physical layer and line protocol bring-up process. This is the only command among the choices that directly changes the administrative state from 'down' to 'up'.
✗Enter interface configuration mode and issue the 'speed 100' command to match the remote interface speed.Wrong answer — click to see why▾
Why this is wrong here
Speed settings do not fix an administratively down interface; the status would not show 'administratively down' if the issue were a speed mismatch.
Why candidates choose this
Candidates might think a speed mismatch is the cause because it is a common layer 1 issue, but the output clearly shows 'administratively down', which is a layer 2 administrative state.
✗Enter interface configuration mode and issue the 'duplex full' command to force full-duplex operation.Wrong answer — click to see why▾
Why this is wrong here
Duplex settings are irrelevant when the interface is shut down; a duplex mismatch would show errors, not 'administratively down'.
Why candidates choose this
Candidates may confuse 'line protocol is down' with a duplex mismatch, but the 'administratively down' keyword clearly indicates the interface was manually disabled.
✗Enter interface configuration mode and issue the 'no keepalive' command to disable keepalives.Wrong answer — click to see why▾
Why this is wrong here
Keepalive configuration does not bring up a shutdown interface; the administratively down state indicates the shutdown command was used.
Why candidates choose this
Candidates might think keepalive mismatch is the problem because it is a common cause of line protocol down, but the 'administratively down' state is distinct and indicates a shutdown command.
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?”
Go deeper
Related to this question
Learn chapter
IPv4 Addressing and Address Classes
Key term
MTU
MTU (Maximum Transmission Unit) is the largest size of a single data packet that can be sent over a network without needing to be fragmented.
Key term
Interface
An interface is a point of connection or interaction between two systems, devices, or software components that allows them to exchange information or signals.
About these practice questions
This 200-301 question is part of Courseiva's 1,389-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
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.