JUNIPER NETWORKS CERTIFIED ASSOCIATE – JUNOS (JNCIA-JUNOS)
CERTIFICATION EXAM COMPLETE PRACTICE TEST BANK QUESTIONS AND
ANSWERS | VERIFIED SOLUTIONS | UPDATED 2026/2027 STUDY GUIDE
Examiner/Administrator: Juniper Networks Certification Program
━━━━━━━━━━━━━━━━━━━━━━━━━━━━
JUNIPER NETWORKS CERTIFIED ASSOCIATE – JUNOS (JNCIA-JUNOS)
2026/2027 EDITION
━━━━━━━━━━━━━━━━━━━━━━━━━━━━
COMPLETE PRACTICE EXAM
120+ MULTIPLE-CHOICE QUESTIONS (SIMULATED BANK SET)
PASSING SCORE: 70%
TESTING TIME: 120 MINUTES
━━━━━━━━━━━━━━━━━━━━━━━━━━━━
TABLE OF CONTENT (MAJOR TOPICS COVERED)
Junos OS Architecture and Navigation
Routing Fundamentals and Concepts
Routing Protocol Operations (OSPF, BGP Basics)
Network Interface Configuration and Management
Security Fundamentals and Firewall Filters
Operational Monitoring and Troubleshooting
Junos CLI Hierarchy and Configuration Modes
Layer 2 Switching Concepts and VLANs
System Administration and Maintenance Tasks
Packet Forwarding and Routing Engine Behavior
Juniper Networks ALIGNED WITH CURRENT JUNOS CERTIFICATION BLUEPRINTS ||
ENTERPRISE NETWORKING FUNDAMENTALS || PROFESSIONAL PRACTICE
EXAMINATION GUIDE || 100% ORIGINAL SIMULATION CONTENT || VERIFIED
EDUCATIONAL BLUEPRINT || COMPREHENSIVE JUNOS PREPARATION MATERIAL ||
DESIGNED FOR CERTIFICATION SUCCESS || PROFESSIONAL EXAMINATION USE
,JUNOS OS ARCHITECTURE & CLI FUNDAMENTALS
Q1. A network engineer logs into a Junos device and notices that configuration
changes are not immediately affecting traffic flow. Which architectural separation
best explains this behavior?
A. Single control plane and forwarding plane
B. Integrated routing and switching engine
C. Separation of control plane and forwarding plane
D. Distributed firewall engine architecture
Correct Answer: 🔴 C. Separation of control plane and forwarding
plane
Explanation: Junos OS uses a dual architecture where the Routing
Engine handles control functions while the Packet Forwarding
Engine handles traffic forwarding. Changes may require commit
operations to propagate from control to forwarding plane. Options
A, B, and D do not reflect Junos architecture.
Q2. Which command mode is required to modify system configuration on a Junos
device?
A. Operational mode
B. Monitor mode
C. Configuration mode
D. Diagnostic mode
Correct Answer: 🔴 C. Configuration mode
Explanation: Configuration mode allows modification of system
settings, interfaces, and protocols. Operational mode is for
monitoring, while diagnostic mode is for troubleshooting.
Q3. What happens when the “commit” command is executed in Junos OS?
A. The system reboots immediately
B. Configuration is validated and applied
C. Only routing protocols restart
D. Forwarding table is erased
,Correct Answer: 🔴 B. Configuration is validated and applied
Explanation: Commit verifies syntax and applies configuration to
the system. It does not reboot the system or erase forwarding
tables.
Q4. Which file stores the active configuration in Junos OS?
A. boot.conf
B. junos.config
C. active.conf
D. candidate configuration database
Correct Answer: 🔴 D. candidate configuration database
Explanation: Junos uses a candidate configuration model that
becomes active after commit. It is not stored in a simple flat file
like other systems.
Q5. Which component is responsible for packet forwarding decisions?
A. Routing Engine
B. Packet Forwarding Engine
C. Management Interface
D. CLI interpreter
Correct Answer: 🔴 B. Packet Forwarding Engine
Explanation: The PFE handles actual packet forwarding using
forwarding tables generated by the Routing Engine.
Q6. Which command displays interface status in operational mode?
A. show configuration interfaces
B. show interfaces terse
C. set interfaces status
D. display interface summary
Correct Answer: 🔴 B. show interfaces terse
Explanation: This command provides a concise view of interface
status and operational state.
Q7. A configuration rollback is performed in Junos OS. What is the primary purpose?
A. Restore factory default settings
, B. Revert to a previous committed configuration
C. Restart routing services
D. Clear system logs
Correct Answer: 🔴 B. Revert to a previous committed
configuration
Explanation: Rollback allows restoring earlier configuration
versions stored in the system.
Q8. Which statement about Junos configuration hierarchy is correct?
A. Flat file structure
B. XML-based hierarchical structure
C. Binary-only configuration
D. Registry-based configuration
Correct Answer: 🔴 B. XML-based hierarchical structure
Explanation: Junos uses a structured hierarchical configuration
model that can be represented in XML.
Q9. What is the purpose of the “commit confirmed” command?
A. Permanently saves configuration
B. Automatically deletes logs
C. Temporarily applies configuration with rollback timer
D. Disables routing protocols
Correct Answer: 🔴 C. Temporarily applies configuration with
rollback timer
Explanation: If confirmation is not provided within the time limit,
configuration automatically reverts.
Q10. Which process runs on the Routing Engine?
A. Packet forwarding only
B. Control plane operations and routing protocols
C. Ethernet switching only
D. Hardware ASIC control
Correct Answer: 🔴 B. Control plane operations and routing
protocols
CERTIFICATION EXAM COMPLETE PRACTICE TEST BANK QUESTIONS AND
ANSWERS | VERIFIED SOLUTIONS | UPDATED 2026/2027 STUDY GUIDE
Examiner/Administrator: Juniper Networks Certification Program
━━━━━━━━━━━━━━━━━━━━━━━━━━━━
JUNIPER NETWORKS CERTIFIED ASSOCIATE – JUNOS (JNCIA-JUNOS)
2026/2027 EDITION
━━━━━━━━━━━━━━━━━━━━━━━━━━━━
COMPLETE PRACTICE EXAM
120+ MULTIPLE-CHOICE QUESTIONS (SIMULATED BANK SET)
PASSING SCORE: 70%
TESTING TIME: 120 MINUTES
━━━━━━━━━━━━━━━━━━━━━━━━━━━━
TABLE OF CONTENT (MAJOR TOPICS COVERED)
Junos OS Architecture and Navigation
Routing Fundamentals and Concepts
Routing Protocol Operations (OSPF, BGP Basics)
Network Interface Configuration and Management
Security Fundamentals and Firewall Filters
Operational Monitoring and Troubleshooting
Junos CLI Hierarchy and Configuration Modes
Layer 2 Switching Concepts and VLANs
System Administration and Maintenance Tasks
Packet Forwarding and Routing Engine Behavior
Juniper Networks ALIGNED WITH CURRENT JUNOS CERTIFICATION BLUEPRINTS ||
ENTERPRISE NETWORKING FUNDAMENTALS || PROFESSIONAL PRACTICE
EXAMINATION GUIDE || 100% ORIGINAL SIMULATION CONTENT || VERIFIED
EDUCATIONAL BLUEPRINT || COMPREHENSIVE JUNOS PREPARATION MATERIAL ||
DESIGNED FOR CERTIFICATION SUCCESS || PROFESSIONAL EXAMINATION USE
,JUNOS OS ARCHITECTURE & CLI FUNDAMENTALS
Q1. A network engineer logs into a Junos device and notices that configuration
changes are not immediately affecting traffic flow. Which architectural separation
best explains this behavior?
A. Single control plane and forwarding plane
B. Integrated routing and switching engine
C. Separation of control plane and forwarding plane
D. Distributed firewall engine architecture
Correct Answer: 🔴 C. Separation of control plane and forwarding
plane
Explanation: Junos OS uses a dual architecture where the Routing
Engine handles control functions while the Packet Forwarding
Engine handles traffic forwarding. Changes may require commit
operations to propagate from control to forwarding plane. Options
A, B, and D do not reflect Junos architecture.
Q2. Which command mode is required to modify system configuration on a Junos
device?
A. Operational mode
B. Monitor mode
C. Configuration mode
D. Diagnostic mode
Correct Answer: 🔴 C. Configuration mode
Explanation: Configuration mode allows modification of system
settings, interfaces, and protocols. Operational mode is for
monitoring, while diagnostic mode is for troubleshooting.
Q3. What happens when the “commit” command is executed in Junos OS?
A. The system reboots immediately
B. Configuration is validated and applied
C. Only routing protocols restart
D. Forwarding table is erased
,Correct Answer: 🔴 B. Configuration is validated and applied
Explanation: Commit verifies syntax and applies configuration to
the system. It does not reboot the system or erase forwarding
tables.
Q4. Which file stores the active configuration in Junos OS?
A. boot.conf
B. junos.config
C. active.conf
D. candidate configuration database
Correct Answer: 🔴 D. candidate configuration database
Explanation: Junos uses a candidate configuration model that
becomes active after commit. It is not stored in a simple flat file
like other systems.
Q5. Which component is responsible for packet forwarding decisions?
A. Routing Engine
B. Packet Forwarding Engine
C. Management Interface
D. CLI interpreter
Correct Answer: 🔴 B. Packet Forwarding Engine
Explanation: The PFE handles actual packet forwarding using
forwarding tables generated by the Routing Engine.
Q6. Which command displays interface status in operational mode?
A. show configuration interfaces
B. show interfaces terse
C. set interfaces status
D. display interface summary
Correct Answer: 🔴 B. show interfaces terse
Explanation: This command provides a concise view of interface
status and operational state.
Q7. A configuration rollback is performed in Junos OS. What is the primary purpose?
A. Restore factory default settings
, B. Revert to a previous committed configuration
C. Restart routing services
D. Clear system logs
Correct Answer: 🔴 B. Revert to a previous committed
configuration
Explanation: Rollback allows restoring earlier configuration
versions stored in the system.
Q8. Which statement about Junos configuration hierarchy is correct?
A. Flat file structure
B. XML-based hierarchical structure
C. Binary-only configuration
D. Registry-based configuration
Correct Answer: 🔴 B. XML-based hierarchical structure
Explanation: Junos uses a structured hierarchical configuration
model that can be represented in XML.
Q9. What is the purpose of the “commit confirmed” command?
A. Permanently saves configuration
B. Automatically deletes logs
C. Temporarily applies configuration with rollback timer
D. Disables routing protocols
Correct Answer: 🔴 C. Temporarily applies configuration with
rollback timer
Explanation: If confirmation is not provided within the time limit,
configuration automatically reverts.
Q10. Which process runs on the Routing Engine?
A. Packet forwarding only
B. Control plane operations and routing protocols
C. Ethernet switching only
D. Hardware ASIC control
Correct Answer: 🔴 B. Control plane operations and routing
protocols
