JNCIS-ENT Layer 2 Security Practice Question
You are troubleshooting port security on an EX Series switch. An interface has been configured with 'action-on-violation shutdown', and a violation occurs. What is the default operational state of the interface after the violation, and how is it restored?
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 interface is disabled and must be manually re-enabled using a clear command or by disabling/re-enabling the interface.
When an interface is shut down due to a port security violation, it enters a disabled state. It remains down until explicitly re-enabled using 'clear ethernet-switching security-violation' or by toggling the interface status.
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 automatically recovers after a default hold-down timer of 300 seconds.
Why it's wrong here
Junos does not automatically recover shutdown interfaces without an explicit clear command or configuration.
- ✓
The interface is disabled and must be manually re-enabled using a clear command or by disabling/re-enabling the interface.
Why this is correct
Correct. The shutdown violation action puts the port in a disabled state requiring administrator intervention.
- ✗
The interface drops violating packets but remains operationally up until manually disabled.
Why it's wrong here
The shutdown action physically disables the interface, not just dropping packets.
- ✗
The interface transitions to a blocked state and flushes its MAC table every 60 seconds until cleared.
Why it's wrong here
The shutdown action completely disables the port rather than transitioning it to a blocked state.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Juniper Networks exam blueprint
This JNCIS-ENT practice question is part of Courseiva's free Juniper Networks 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 JNCIS-ENT exam.