The answer is that the port remains up and operational. This is correct because port security restrict mode is designed to drop frames from unauthorized MAC addresses while logging the violation and incrementing the violation counter, but it deliberately avoids taking the port down—unlike shutdown mode, which err-disables the interface. On the CCNA 200-301 v2 exam, this distinction is a frequent trap: many candidates assume any violation disables the port, but restrict is the intermediate behavior that keeps connectivity alive for legitimate traffic. A common memory tip is to think of “restrict” as “restrict the bad, keep the good flowing”—the port stays up, only the violating frames are silently dropped.
CCNA Network Services and Security Practice Question
This 200-301 practice question tests your understanding of network services and security. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. A key principle to apply: port security on Cisco switches controls access by limiting the number of MAC addresses allowed on a switch port to prevent unauthorized devices from connecting.. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A switch port is configured with port-security violation mode restrict. Which two statements are true when an unauthorized MAC address appears?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Frames from the unauthorized MAC are dropped
Restrict drops frames from violating MAC addresses and can increment the violation counter while keeping the port up. Shutdown would err-disable the port instead.
Key principle: Port security on Cisco switches controls access by limiting the number of MAC addresses allowed on a switch port to prevent unauthorized devices from connecting.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Frames from the unauthorized MAC are dropped
Why this is correct
Restrict does not allow the violating traffic through.
Related concept
Port security on Cisco switches controls access by limiting the number of MAC addresses allowed on a switch port to prevent unauthorized devices from connecting.
✓
The port remains up
Why this is correct
Restrict does not err-disable the interface.
Related concept
Port security on Cisco switches controls access by limiting the number of MAC addresses allowed on a switch port to prevent unauthorized devices from connecting.
✗
The interface immediately goes into err-disabled state
Why it's wrong here
That is shutdown mode behavior.
✗
The switch converts the port to a trunk automatically
The violation mode changes itself to shutdown after three attempts
Why it's wrong here
That is not automatic behavior.
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.
✓Frames from the unauthorized MAC are droppedCorrect answer▾
Why this is correct
Restrict does not allow the violating traffic through.
✗The interface immediately goes into err-disabled stateWrong answer — click to see why▾
Why this is wrong here
The err-disabled state is characteristic of the shutdown violation mode, not restrict. In restrict mode, the port remains up and only drops violating traffic while logging the event.
Why candidates choose this
Students often confuse restrict with shutdown because both are port security violation modes. They may assume that any violation leads to an err-disabled state, but restrict is designed to avoid that.
✗The switch converts the port to a trunk automaticallyWrong answer — click to see why▾
Why this is wrong here
Port security does not change the port's operational mode; it only controls MAC address access. Converting a port to a trunk is unrelated to port security and requires explicit configuration.
Why candidates choose this
Some might think that port security automatically adjusts the port type to handle multiple VLANs, but that is not a function of port security. Trunking is configured separately.
✗The violation mode changes itself to shutdown after three attemptsWrong answer — click to see why▾
Why this is wrong here
Port security violation modes do not automatically change. The mode is statically configured and remains the same regardless of the number of violations. There is no automatic escalation from restrict to shutdown.
Why candidates choose this
Students might think that after multiple violations, the switch escalates the response, similar to how some security features have thresholds. However, port security does not have such automatic mode changes.
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?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
Do not confuse restrict with shutdown mode; restrict does not disable the port.
Detailed technical explanation
How to think about this question
Port security is a fundamental feature in Cisco switches that enhances network security by restricting input to an interface based on MAC addresses. It allows administrators to specify which MAC addresses are allowed on a port, limiting access to authorized devices only. When an unauthorized MAC address attempts to send traffic, the switch reacts based on the configured violation mode, which can be protect, restrict, or shutdown.
In restrict mode, the switch drops frames from unauthorized MAC addresses and increments a violation counter, but crucially, it keeps the port operational. This behavior contrasts with shutdown mode, where the port is immediately placed into an err-disabled state, effectively shutting down the interface until manually re-enabled. Restrict mode thus provides a balance between security and availability by blocking unauthorized traffic without disrupting legitimate communication on the port.
A common exam trap is confusing restrict mode with shutdown mode. Candidates might incorrectly assume that restrict mode disables the port after violations, but it only drops unauthorized frames and logs violations. This distinction is important in practical networking scenarios where maintaining uptime is critical, and administrators want to monitor violations without causing network outages. Understanding this behavior helps in designing secure yet resilient network environments.
KKey Concepts to Remember
Port security on Cisco switches controls access by limiting the number of MAC addresses allowed on a switch port to prevent unauthorized devices from connecting.
The restrict violation mode drops frames from unauthorized MAC addresses and increments the violation counter without disabling the port.
The shutdown violation mode immediately places the port into an err-disabled state, effectively disabling the interface upon a security violation.
Port security violation modes do not automatically change based on the number of violations; the configured mode remains until manually changed.
Port security does not convert access ports to trunk ports automatically under any violation mode.
When a port is in restrict mode, it continues forwarding legitimate traffic from authorized MAC addresses while blocking unauthorized ones.
Violation counters in restrict mode help network administrators monitor security breaches without causing network downtime.
Understanding the difference between restrict and shutdown modes is critical for maintaining network availability and security balance.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Port security on Cisco switches controls access by limiting the number of MAC addresses allowed on a switch port to prevent unauthorized devices from connecting.
Real-world example
How this comes up in practice
A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Review port security on Cisco switches controls access by limiting the number of MAC addresses allowed on a switch port to prevent unauthorized devices from connecting., then practise related 200-301 questions on the same topic to reinforce the concept.
Network Services and Security — This question tests Network Services and Security — Port security on Cisco switches controls access by limiting the number of MAC addresses allowed on a switch port to prevent unauthorized devices from connecting..
What is the correct answer to this question?
The correct answer is: Frames from the unauthorized MAC are dropped — Restrict drops frames from violating MAC addresses and can increment the violation counter while keeping the port up. Shutdown would err-disable the port instead.
What should I do if I get this 200-301 question wrong?
Review port security on Cisco switches controls access by limiting the number of MAC addresses allowed on a switch port to prevent unauthorized devices from connecting., then practise related 200-301 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
Port security on Cisco switches controls access by limiting the number of MAC addresses allowed on a switch port to prevent unauthorized devices from connecting.
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