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Troubleshooting practice questions

Practise Juniper Networks Certified Associate Junos JNCIA-Junos Troubleshooting practice questions — original exam-style scenarios with answer choices, explanations, and analysis of common mistakes.

Courseiva uses original exam-style practice questions designed for learning and revision. The goal is to understand the concepts, recognise exam patterns, and improve through explanations — not memorise copied exam dumps.

Reviewed byJohnson Ajibi· MSc IT Security
20 questionsDomain: Troubleshooting
Practice 10 questionsBrowse domain →

What the exam tests

What to know about Troubleshooting

Troubleshooting questions test whether you can apply the concept in context, not just recognise a definition.

How the topic appears in realistic exam-style scenarios.

Which detail in the question changes the correct answer.

How to eliminate plausible but wrong options.

How to connect the question back to the wider exam objective.

Watch out for

Common Troubleshooting exam traps

  • ▸Answering from memory before reading the full scenario.
  • ▸Missing a constraint such as cost, availability, security, scope or command context.
  • ▸Choosing a broad answer when the question asks for the most specific fix.
  • ▸Ignoring why the wrong options are tempting.

Practice set

Troubleshooting questions

20 questions · select your answer, then reveal the explanation

Question 1easymultiple choice
Review the full routing breakdown →

A network engineer is troubleshooting a connectivity issue and wants to see the active routes in the routing table. Which Junos CLI command should they use?

Question 2mediummultiple choice
Review the full routing breakdown →

A network engineer is troubleshooting a reachability issue between two directly connected routers. Both routers have IP addresses configured on their interfaces and the interfaces are up. Which command would the engineer use to verify the routing table entry for the remote network?

Question 3mediummulti select
Read the full Troubleshooting explanation →

Which TWO statements correctly describe the behavior of the Junos CLI operational mode?

Question 4mediummultiple choice
Review the full routing breakdown →

A network engineer is troubleshooting connectivity between two directly connected Juniper routers. The interface on Router A shows 'up' but no packets are being received from Router B. Which command should the engineer use on Router A to check if the interface is expecting to receive a specific encapsulation type?

Question 5hardmultiple choice
Review the full OSPF breakdown →

You are a junior network engineer at a company that uses Juniper MX routers. You are troubleshooting a connectivity issue on a branch router. The branch router has two upstream links to the corporate network: ge-0/0/0 (10.1.1.1/30, connected to core router A) and ge-0/0/1 (10.1.1.5/30, connected to core router B). The branch router runs OSPF and has a default route learned from both upstream routers. The routing table shows two equal-cost default routes via both next hops. However, traffic from the branch to the corporate network is experiencing intermittent high latency and some packet loss. You suspect that asymmetric routing is causing issues because the return traffic is not following the same path. You want to influence the router to prefer one upstream link for all traffic to the corporate network. You have decided to adjust the OSPF metric on the branch router to make the link to core router A more preferred. You are in configuration mode on the branch router. Which single configuration change will accomplish this goal?

Question 6mediummulti select
Read the full Troubleshooting explanation →

Which TWO statements correctly describe the use of the 'monitor traffic' command in Junos?

Question 7hardmultiple choice
Review the full OSPF breakdown →

A network engineer is troubleshooting OSPF adjacencies between two Juniper routers. The routers are directly connected and have matching OSPF configurations except for the router IDs. Router A has router-id 10.0.0.1, Router B has router-id 10.0.0.2. The adjacency remains in the EXSTART state. What is the most likely cause?

Question 8hardmultiple choice
Read the full Troubleshooting explanation →

During troubleshooting, an engineer needs to view real-time logging messages on a Junos device. Which command should be used?

Question 9hardmultiple choice
Review the full routing breakdown →

A junior engineer is troubleshooting a routing issue and wants to see the route table for IPv4 unicast routes. Which command will display this information?

Question 10hardmultiple choice
Open the full BGP breakdown →

During troubleshooting, an engineer notices that BGP sessions are flapping. They suspect that the issue might be related to the maximum number of routes allowed. To see if the BGP import policy is rejecting routes, which operational command would provide immediate insight?

Question 11mediummultiple choice
Read the full NAT/PAT explanation →

A junior engineer is troubleshooting connectivity issues and wants to trace the path packets take to a remote destination. Which Junos command should be used?

Question 12easymultiple choice
Read the full Troubleshooting explanation →

An administrator wants to navigate to the configuration mode to make changes to the device. Which command should be used?

Question 13mediummultiple choice
Review the full routing breakdown →

A network administrator is troubleshooting high CPU usage on a Juniper router. Which command helps identify which process is consuming the most CPU?

Question 14mediummatching
Read the full Troubleshooting explanation →

Match each Junos CLI operational mode command to its function.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Displays brief interface status and configuration

Displays the routing table

Displays the current active configuration

Displays system log messages

Captures and displays live traffic on an interface

Question 15easymultiple choice
Read the full Troubleshooting explanation →

A network administrator is troubleshooting high latency on a link. Which command provides real-time interface statistics?

Question 16mediummultiple choice
Open the full VLAN trunking answer →

A network engineer is troubleshooting connectivity between two VLANs on the same Juniper EX switch. Hosts in VLAN 100 cannot ping hosts in VLAN 200. The switch has an IRB interface configured for each VLAN. Which configuration is most likely missing?

Question 17hardmulti select
Read the full Troubleshooting explanation →

A junior administrator is learning to navigate the Junos CLI. Which three statements about CLI modes are correct? (Choose three.)

Question 18mediummultiple choice
Open the full BGP breakdown →

A network engineer is troubleshooting a BGP session that is not establishing. They want to see the BGP configuration details for peer 10.0.0.1. They type 'show configuration protocols bgp group external peer 10.0.0.1' but receive 'error: syntax error'. They are in operational mode. What is the most likely issue?

Question 19mediummultiple choice
Open the full VLAN trunking answer →

You are troubleshooting a network connectivity issue at a medium-sized company that uses Juniper EX4300 switches. Users in VLAN 100 (10.10.100.0/24) report that they cannot access a server in VLAN 200 (10.10.200.0/24). The switch has IRB interfaces configured for both VLANs and is acting as the default gateway. The IRB interfaces are up and have correct IP addresses. The server and users have correct IP configurations. 'show arp' on the switch shows incomplete entries for some hosts in VLAN 100. 'show ethernet-switching table' shows MAC addresses for users are present on the correct access ports. However, pings from the switch to a user in VLAN 100 fail. What is the most likely issue?

Question 20hardmultiple choice
Open the full BGP breakdown →

A network engineer is troubleshooting a BGP routing issue. The router receives a route to 172.16.0.0/16 from two BGP peers with different local preferences. The route from peer A has local preference 200, and from peer B has local preference 100. The router selects the route from peer A. What is the next step in BGP path selection if the local preferences were equal?

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Focused Troubleshooting sessions

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Frequently asked questions

What does the JNCIA-JUNOS exam test about Troubleshooting?
Troubleshooting questions test whether you can apply the concept in context, not just recognise a definition.
How should I use these practice questions?
Select your answer before revealing the explanation. Then read why each option is right or wrong — this active recall approach builds retention far faster than re-reading notes.
Can I practise just Troubleshooting questions in a focused session?
Yes — the session launcher on this page draws every question from the Troubleshooting domain. Use a 10-question session first to gauge your baseline, then move to 20 or 30 once the weak spots are clear.
Where can I practise other JNCIA-JUNOS topics?
Use the topic links above to move to related areas, or go back to the JNCIA-JUNOS question bank to see all topics.
Are these real exam questions or dumps?
These are original practice questions written to test the same concepts the JNCIA-JUNOS exam covers. They are not copied from any real exam or dump site.