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Question 1

Score: 0/0

In an Ethernet network built with a hub, how many collision domains exist across the connected ports?

One collision domain per port

One shared collision domain

One collision domain per VLAN

Zero collision domains because hubs are Layer 1 devices

to track

2026 Statistics

Key Facts: JNCIA-Junos Exam

Multiple-Choice Questions

Juniper exam page

90 min

Exam Length

Juniper exam page

$200

Associate Exam Fee

Juniper purchase options

3 years

Certification Validity

Juniper recertification policy

7 domains

Published Objective Areas

Juniper exam objectives

Apr 6, 2026

JN0-106 Start Date

Juniper training news

As of March 11, 2026, the current public JNCIA-Junos exam remains JN0-105 through April 5, 2026, and Juniper has announced JN0-106 starting April 6, 2026. The exam is 65 multiple-choice questions in 90 minutes through Pearson VUE. Juniper publishes seven objective domains, but it does not publicly publish official percentage weightings or a numeric passing score.

Sample JNCIA-Junos Practice Questions

Try these sample questions to test your JNCIA-Junos exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 200+ question experience with AI tutoring.

1In an Ethernet network built with a hub, how many collision domains exist across the connected ports?

A.One collision domain per port

B.One shared collision domain

C.One collision domain per VLAN

D.Zero collision domains because hubs are Layer 1 devices

Explanation: A hub repeats bits out all ports, so every attached device shares the same collision domain. That means only one device can successfully transmit at a time without collisions on that segment.

2Which device boundary typically separates broadcast domains in an Ethernet network?

A.A repeater port

B.A switch port in the same VLAN

C.A router interface

D.A NIC operating in full duplex

Explanation: Routers do not forward Layer 2 broadcasts by default, so each routed interface forms a broadcast-domain boundary. Switch ports in the same VLAN remain in the same broadcast domain unless routing occurs between them.

3Which protocol is connection-oriented and uses acknowledgments to provide reliable delivery?

A.UDP

B.IP

C.TCP

D.Ethernet

Explanation: TCP establishes a session and uses sequence numbers, acknowledgments, and retransmissions to provide reliable delivery. UDP is connectionless and sends datagrams without built-in session setup or delivery confirmation.

4Which prefix identifies IPv6 link-local addresses?

A.FE80::/10

B.FC00::/7

C.2000::/3

D.FF00::/8

Explanation: IPv6 link-local addresses use the FE80::/10 prefix and are valid only on the local link. Routers do not forward them, which makes them useful for neighbor discovery and local control traffic.

5Which IPv4 address is part of a private address range and is valid for host use?

A.172.20.14.9

B.169.254.10.8

C.198.51.100.25

D.224.0.0.5

Explanation: 172.20.14.9 falls within the private 172.16.0.0/12 range defined by RFC 1918. A 169.254.0.0/16 address is link-local, 198.51.100.0/24 is documentation space, and 224.0.0.0/4 is multicast.

6How many usable host addresses are available in an IPv4 /27 subnet?

A.14

B.30

C.32

D.62

Explanation: A /27 leaves 5 host bits, which creates 32 total addresses in the subnet. After subtracting the network and broadcast addresses, 30 usable host addresses remain.

7A host address is 198.51.100.70/26. Which subnet contains this host?

A.198.51.100.0/26

B.198.51.100.64/26

C.198.51.100.96/26

D.198.51.100.128/26

Explanation: A /26 subnet increments by 64 addresses, so the ranges begin at .0, .64, .128, and .192. Because .70 falls between .64 and .127, the correct subnet is 198.51.100.64/26.

8Which single summary route covers both 192.0.2.0/24 and 192.0.3.0/24?

A.192.0.0.0/22

B.192.0.2.0/24

C.192.0.2.0/23

D.192.0.3.0/23

Explanation: Two consecutive /24 networks can be summarized into one /23 when they align on the correct binary boundary. In this case, 192.0.2.0/23 covers addresses from 192.0.2.0 through 192.0.3.255.

9A router has these routes: 203.0.113.0/24 via ge-0/0/0, 203.0.113.128/25 via ge-0/0/1, 203.0.113.128/26 via ge-0/0/2, and 0.0.0.0/0 via ge-0/0/3. Which route is used for destination 203.0.113.190?

A.203.0.113.0/24 via ge-0/0/0

B.203.0.113.128/25 via ge-0/0/1

C.203.0.113.128/26 via ge-0/0/2

D.0.0.0.0/0 via ge-0/0/3

Explanation: Routers use longest-prefix match, so the most specific matching route wins. Address 203.0.113.190 matches the /24, the /25, and the /26, but the /26 is the longest and is therefore selected.

10When an Ethernet switch receives a frame with an unknown unicast destination MAC address, what does it do by default?

A.Floods the frame out all other ports in the same VLAN

B.Drops the frame immediately

C.Sends the frame to all VLANs

D.Forwards the frame only to the default gateway

Explanation: If the switch does not yet know the destination MAC location, it floods the unknown unicast frame within the originating VLAN. Once the destination replies, the switch learns the MAC-to-port mapping and can forward future frames more selectively.

About the JNCIA-Junos Exam

JNCIA-Junos is Juniper Networks' associate-level certification for networking professionals who need a solid foundation in Junos OS. The exam covers networking fundamentals, Junos architecture, CLI and J-Web usage, base configuration, operational monitoring and maintenance, routing basics, and routing policy plus firewall filters.

Questions

65 scored questions

Time Limit

90 minutes

Passing Score

Unpublished by Juniper (pass/fail result shown immediately)

Exam Fee

$200 (Juniper Networks / Pearson VUE)

JNCIA-Junos Exam Content Outline

Est. 9%

Networking Fundamentals

Collision and broadcast domains, router and switch functions, Ethernet, Layer 2 and Layer 3 addressing, IPv4 and IPv6, subnetting and supernetting, decimal-to-binary conversion, longest match routing, CoS, and connection-oriented versus connectionless protocols

Est. 8.5%

Junos OS Fundamentals

Junos software architecture, control plane and forwarding plane, routing engine, packet forwarding engine, transit traffic processing, and exception traffic

Est. 20%

User Interfaces

CLI modes, navigation, help features, output filtering, candidate versus active configuration, rollback and compare operations, file load and save workflow, and core J-Web functionality

Est. 21%

Configuration Basics

Factory-default state, initial configuration, user accounts, login classes, authentication methods, interface types and properties, configuration groups, NTP, SNMP, syslog, archival, tracing, rescue configuration, and basic device setup

Est. 13.5%

Operational Monitoring and Maintenance

Show and monitor commands, interface statistics and errors, built-in network tools, Junos installation and upgrades, safe power operations, and root password recovery

Est. 18%

Routing Fundamentals

Traffic forwarding concepts, routing tables versus forwarding tables, route preference, routing instances, static routing, and the role of dynamic routing protocols

Est. 10%

Routing Policy and Firewall Filters

Default routing policies, import and export policy behavior, policy terms and actions, firewall filter structure, packet matching, filter effects, and unicast reverse-path forwarding

How to Pass the JNCIA-Junos Exam

What You Need to Know

Passing score: Unpublished by Juniper (pass/fail result shown immediately)
Exam length: 65 questions
Time limit: 90 minutes
Exam fee: $200

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

JNCIA-Junos Study Tips from Top Performers

1Practice the Junos CLI every day so operational mode, configuration mode, hierarchy navigation, and commit workflow become automatic.

2Memorize candidate versus active configuration behavior, rollback commands, rescue configuration, and how compare or load operations affect the candidate config.

3Be fluent in core networking math and logic: subnetting, IPv4 and IPv6 basics, longest-prefix match, and route preference comparisons.

4Know the default and common uses of NTP, SNMP, syslog, user accounts, login classes, and interface configuration because Juniper tests foundational system administration heavily.

5Spend time reading and interpreting `show` output rather than only memorizing commands; JNCIA-Junos questions often present operational state and ask what it means.

6Treat routing policy and firewall filters as logic exercises: understand terms, match conditions, actions, evaluation order, and the difference between route processing and packet filtering.

Frequently Asked Questions

What is the current JNCIA-Junos exam code in 2026?

Juniper announced a JNCIA-Junos exam update on March 2, 2026. As of March 11, 2026, JN0-105 is still the active exam through April 5, 2026, and JN0-106 becomes active on April 6, 2026. The objectives remain centered on Junos OS fundamentals, CLI operation, configuration, monitoring, routing, and routing policy.

How many questions are on the JNCIA-Junos exam, and how long do you get?

Juniper lists the JNCIA-Junos exam as 65 multiple-choice questions with a 90-minute time limit. The exam is delivered in English through Pearson VUE. Plan your pacing around about 80 seconds per question, leaving a few minutes at the end for review.

What is the JNCIA-Junos passing score?

Juniper does not publicly publish a numeric passing score for JNCIA-Junos. Instead, candidates receive immediate pass or fail status after the exam. That means your study goal should be broad coverage of all seven objective domains rather than trying to reverse-engineer a target percentage.

Does Juniper publish official domain percentage weightings?

No. Juniper publicly publishes the JNCIA-Junos objective domains and detailed subtopics, but it does not publicly publish official percentage weights for those domains. The study emphasis shown on this page is an estimate based on objective breadth and hands-on importance, not an official Juniper weighting.

What topics matter most for JNCIA-Junos prep?

The highest-leverage topics are CLI workflow, candidate versus active configuration, rollback and rescue operations, user and system setup, interface basics, monitoring commands, routing tables and route preference, static routing, and routing policy or firewall filter logic. Candidates who already know general networking often lose points on Junos-specific operational behavior rather than on IPv4 or subnetting.

How long should I study for JNCIA-Junos?

Most candidates with general networking experience can prepare in about 40 to 70 hours over 3 to 6 weeks. If Junos is your first network operating system, budget extra time for CLI navigation, configuration hierarchy, commit workflow, rollback behavior, and routing policy syntax. Repeated practice with realistic command output matters more than memorizing isolated facts.