Practice Exam JN0-106: JNCIA-Junos

Question bank: 100 · timed mock exam: 90 min

Official exam page on the vendor's site (opens in a new tab) Official prep course (opens in a new tab)

Compare: JN0-106 vs AZ-700

  • Networking Fundamentals 19 questions
  • Configuration Basics 18 questions
  • Routing Policy and Firewall Filters 18 questions
  • User Interfaces 16 questions
  • Operational Monitoring and Maintenance 11 questions
  • Routing Fundamentals 10 questions
  • Junos OS Fundamentals 8 questions
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How to prepare for JNCIA-Junos with InfraPrep

The 100 questions cover 7 domains: Networking Fundamentals, Configuration Basics, Routing Policy and Firewall Filters, User Interfaces, Operational Monitoring and Maintenance, Routing Fundamentals, Junos OS Fundamentals. 25 of them are free, without an account.

Study mode

Answer at your pace: each answer is corrected straight away, with an explanation and the link to the documentation it relies on.

Exam mode

A timed exam of 90 minutes, with a question map to flag and come back to questions before you submit.

Results by domain

Your score is broken down by domain, so you know what to review first.

Original questions

Every question is written from the public documentation, never copied from the exam. You can contest an answer from study mode.

10 free sample questions

Question 1 Networking Fundamentals

A small office connects twelve hosts to one Ethernet LAN. No bridging features and no VLANs are configured anywhere on the LAN. A host sends a frame to the Layer 2 broadcast address. Which statement describes the scope of this traffic?

  1. All devices on the LAN are in one broadcast domain and detect the frame
  2. Each switch port is its own broadcast domain, so only the sender sees it
  3. Only hosts configured with the same IP subnet mask receive the frame
  4. The frame is dropped until every host has a matching ARP table entry
Show the answer and the explanation

Correct answer: A

The documentation states that without bridging and VLANs, all devices on the Ethernet LAN share a single broadcast domain and detect all packets on the LAN.

Source: official documentation

Question 2 Junos OS Fundamentals

Which characteristic of the Junos OS software architecture explains why the failure of one software process usually has little effect on the others?

  1. All daemons share one memory space that the kernel restores after a fault
  2. Software functions run as separate processes in protected memory spaces
  3. The Packet Forwarding Engine takes over the tasks of any failed process
  4. The rescue configuration is loaded to restart the failed process quickly
Show the answer and the explanation

Correct answer: B

Junos OS keeps software functions in separate processes, and each module runs in its own protected memory space, so one module cannot disrupt another.

Source: official documentation

Question 3 User Interfaces

An administrator has typed only the first letters of a CLI command and wants Junos OS to complete it. Which keys perform command completion?

  1. The question mark key, pressed twice in a row
  2. The Esc key followed by the Enter key
  3. The Tab key or the spacebar
  4. The pipe symbol followed by the Enter key
Show the answer and the explanation

Correct answer: C

The CLI completes a partially typed command or option when you press the Tab key or the spacebar.

Source: official documentation

Question 4 Configuration Basics

A new Junos device is unpacked, installed and powered on for the first time. Which configuration does it use at this first boot?

  1. The rescue configuration stored by the manufacturer
  2. The factory-default configuration, loaded automatically
  3. An empty configuration that has to be typed at the console
  4. The configuration numbered 49 in the rollback history
Show the answer and the explanation

Correct answer: B

The factory-default configuration is the first configuration of the device and is loaded automatically the first time the device is installed and powered on.

Source: official documentation

Question 5 Operational Monitoring and Maintenance

An operator wants to watch interface counters change live during a traffic test, refreshed every second. Which command does this?

  1. show interfaces extensive
  2. monitor traffic
  3. monitor interface
  4. monitor start
Show the answer and the explanation

Correct answer: C

monitor interface displays real-time statistics about interfaces and updates them every second.

Source: official documentation

Question 6 Routing Fundamentals

A router learns 10.1.1.0/24 from three sources: an OSPF internal route, a BGP route and a static route. No preferences have been changed. Which route becomes active?

  1. The OSPF internal route, with preference 10
  2. The BGP route, with preference 170
  3. The static route, with preference 5
  4. All three, installed as equal-cost paths
Show the answer and the explanation

Correct answer: C

The active route is generally the one with the lowest preference value; static routes have a default preference of 5, lower than OSPF internal (10) and BGP (170).

Source: official documentation

Question 7 Routing Policy and Firewall Filters

A router runs RIP with its neighbors and also has several static routes. No routing policy has been configured. Are the static routes advertised to the RIP neighbors?

  1. Yes, because RIP exports all active routes from the routing table
  2. No, the default RIP export policy rejects them; an export policy is needed
  3. Yes, because static routes are exported by every protocol by default
  4. Yes, but only to RIP neighbors that share the same IP subnet
Show the answer and the explanation

Correct answer: B

The default export policy for RIP rejects everything; to export routes into RIP, an export policy for RIP must be configured.

Source: official documentation

Question 8 Networking Fundamentals

A workstation knows the IPv4 address of its default gateway but not the gateway's hardware address. Which protocol resolves this, and how does it reach the gateway?

  1. ICMP, which sends unicast echo requests to learn the gateway MAC address
  2. ARP, which uses broadcasting to map MAC addresses to IP addresses
  3. NTP, which multicasts the gateway MAC address to all hosts on the link
  4. SNMP, which polls the gateway MIB to read its interface MAC address
Show the answer and the explanation

Correct answer: B

ARP uses broadcasting to map MAC addresses to IP addresses and dynamically binds the logical IP address to the correct MAC address.

Source: official documentation

Question 9 Junos OS Fundamentals

A packet enters ge-0/0/1 of a Junos router and is forwarded out ge-0/0/2 toward a server on another network. The packet is not addressed to the router itself. How does Junos OS classify this packet, and which component handles its flow?

  1. As a data packet, handled by the Packet Forwarding Engine
  2. As a local packet, handled by the Routing Engine
  3. As a local packet, handled by the loopback interface lo0
  4. As a data packet, handled by the routing protocol process
Show the answer and the explanation

Correct answer: A

Data packets are those that transit the router from a source to a destination, and the Packet Forwarding Engine handles the flow of data packets in and out of the physical interfaces.

Source: official documentation

Question 10 User Interfaces

An administrator is working at [edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0] in configuration mode. With a single command, the administrator wants to move directly to the top level of the configuration hierarchy. Which command should be used?

  1. up
  2. top
  3. exit
  4. quit
Show the answer and the explanation

Correct answer: B

The top command moves directly to the top level of the hierarchy, whatever the current depth.

Source: official documentation

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