Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
On a user access port, port security is configured with a maximum of 2 MAC addresses and violation mode restrict. A third unauthorized device is connected through a small unmanaged switch. What happens?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
The port goes err-disabled immediately.
That behavior matches shutdown mode, not restrict.
B
Best answer
Traffic from the unauthorized MAC is dropped, but the interface stays up.
That is the expected behavior in restrict mode.
C
Distractor review
The switch learns the third MAC after aging out the first one instantly.
Aging does not occur instantly just because a new device appears.
D
Distractor review
All traffic from the port is flooded to the VLAN for analysis.
Port security does not work that way.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is confusing the restrict violation mode with shutdown mode. Candidates often mistakenly believe that any violation causes the port to go err-disabled immediately. However, restrict mode only drops unauthorized traffic and keeps the interface up, allowing legitimate devices to continue communicating. This misunderstanding can lead to selecting the wrong answer, especially when the question specifies restrict mode. Remember that shutdown mode is the one that disables the port on violation, not restrict mode. Misreading the violation mode or assuming default behavior without verification is a frequent pitfall.
Technical deep dive
How to think about this question
Port security is a Layer 2 feature on Cisco switches that restricts input to an interface by limiting and identifying MAC addresses of the stations allowed to access the port. It helps prevent unauthorized devices from connecting to the network by controlling which MAC addresses can send traffic through a user access port. When port security is enabled, the switch learns and stores allowed MAC addresses, either dynamically or statically, and enforces limits on the number of MAC addresses per port. The violation mode determines the switch's response when an unauthorized MAC address is detected. In restrict mode, the switch drops traffic from unauthorized MAC addresses but keeps the interface operational. It also increments a violation counter and can generate syslog messages or SNMP traps for network monitoring. This contrasts with shutdown mode, where the port is immediately disabled (err-disabled) upon violation. The maximum MAC address limit is strictly enforced, so connecting a third device through an unmanaged switch does not allow learning beyond the configured limit. A common exam trap is confusing restrict mode with shutdown mode. Many candidates incorrectly assume that any violation causes the port to shut down immediately. However, restrict mode is designed to maintain network availability by dropping unauthorized traffic without disabling the port. Practically, this allows network administrators to monitor violations and respond without disrupting legitimate users. Understanding this distinction is crucial for correctly answering questions about port security behavior under different violation modes.
KKey Concepts to Remember
- Port security on a user access port limits the number of MAC addresses that can be learned or allowed on that interface to prevent unauthorized access.
- When port security violation mode is set to restrict, the switch drops traffic from unauthorized MAC addresses but keeps the interface operational.
- In restrict mode, the switch increments a violation counter and can generate syslog messages or SNMP traps for network monitoring.
- Shutdown violation mode causes the port to go err-disabled immediately upon detecting an unauthorized MAC address, unlike restrict mode.
- Connecting multiple devices through an unmanaged switch does not bypass the maximum MAC address limit configured on a port security-enabled interface.
- Port security violation modes determine how the switch reacts to unauthorized MAC addresses, affecting network availability and security monitoring.
- The switch does not instantly age out learned MAC addresses to accommodate new ones when the maximum limit is reached on a port security-enabled interface.
- Understanding the difference between restrict and shutdown violation modes is essential to correctly predict port security behavior in Cisco networks.
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.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
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Question 3
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FAQ
Questions learners often ask
What does this 200-301 question test?
Port security on a user access port limits the number of MAC addresses that can be learned or allowed on that interface to prevent unauthorized access.
What is the correct answer to this question?
The correct answer is: Traffic from the unauthorized MAC is dropped, but the interface stays up. — In restrict mode, frames from unknown MAC addresses are dropped, the violation counter increments, and logging or SNMP traps can be generated. Unlike shutdown mode, the interface does not go err-disabled.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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