Free Junos, Associate (JN0-106) Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Junos, Associate (JN0-106) practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1What network boundary does a VLAN establish at Layer 2?

   1. A. A separate broadcast domain
   2. B. A separate TCP connection
   3. C. A separate IP routing protocol
   4. D. A separate physical cabling medium

   Answer: A

   Explanation: The VLAN definition says nodes "form separate broadcast domains." A VLAN separates Layer 2 broadcast reachability; it does not itself establish a transport connection, select a routing protocol, or require a separate cable.

   Reference: Layer 2 Networking — Understanding VLANs

2. 2On hardware-based Junos routing platforms, which technology does the Packet Forwarding Engine use for high-speed packet switching and route lookups?

   1. A. General-purpose Routing Engine software
   2. B. Application-specific integrated circuits
   3. C. General-purpose external server software
   4. D. Per-packet routing protocol calculations

   Answer: B

   Explanation: The architecture documentation identifies "ASICs" in the PFE. Specialized circuits provide hardware packet forwarding; the Routing Engine computes routing information rather than executing its routing algorithms for every transit packet.

   Reference: Junos OS Architecture Overview — Packet Forwarding Engine

3. 3Which character normally ends the Junos CLI prompt in operational mode?

   1. A. # (hash sign)
   2. B. % (percent sign)
   3. C. > (greater-than sign)
   4. D. $ (dollar sign)

   Answer: C

   Explanation: The CLI tour calls the operational prompt a "right-angle bracket". The hash identifies configuration mode; percent and dollar signs are associated with other command-shell contexts.

   Reference: Getting Started: A Quick Tour of the CLI — Switch Between Operational Mode and Configuration Mode

4. 4What Junos configuration object primarily defines a user's CLI access privileges and permissions?

   1. A. A routing instance
   2. B. A configuration group name
   3. C. A login class
   4. D. A syslog facility

   Answer: C

   Explanation: The class reference defines a "login class" for users according to needed permissions. Routing instances separate routing contexts, configuration groups provide inheritance, and syslog facilities categorize messages rather than grant CLI privileges.

   Reference: class (Defining Login Classes) — Description

5. 5Which command displays the software version running on a Junos device?

   1. A. show system uptime
   2. B. show chassis hardware
   3. C. show version
   4. D. show system storage

   Answer: C

   Explanation: The operational overview lists "show version" for running software versions. Uptime, hardware inventory, and filesystem usage answer different maintenance questions.

   Reference: CLI Operational Mode Overview — Table 1, Software version

6. 6Which statement correctly distinguishes the Junos routing table from the forwarding table?

   1. A. The routing table keeps only selected routes; the forwarding table keeps all route candidates
   2. B. The routing table contains route candidates; the forwarding table contains selected forwarding routes
   3. C. The routing table learns local routes only; the forwarding table independently learns remote routes
   4. D. The routing table switches packets directly; the forwarding table stores only backup route candidates

   Answer: B

   Explanation: Juniper calls forwarding-table entries the "routes actually used" for forwarding. The routing table collects candidate routes and selects active ones; the forwarding table is populated for packet forwarding rather than independently learning remote routes or holding only backup candidates.

   Reference: Routing Databases Overview — Introduction, Routing table and Forwarding table definitions; Forwarding Tables

7. 7Which distinction correctly describes the primary objects evaluated by Junos routing policies and stateless firewall filters?

   1. A. Routing policies evaluate routes; firewall filters evaluate packets
   2. B. Routing policies evaluate packets; firewall filters evaluate routes
   3. C. Both evaluate routes to decide routing-table admission
   4. D. Both evaluate packets to maintain transport-session state

   Answer: A

   Explanation: Juniper distinguishes "routing information" from "packets". Routing policies control route selection and advertisement, while firewall filters control packet acceptance and forwarding. Neither mechanism primarily authenticates users or evaluates chassis sensors.

   Reference: Comparison of Routing Policies and Firewall Filters — Table 1 Purpose; Table 2 Control points

8. 8On shared Ethernet using CSMA/CD, what does collision detection monitor?

   1. A. Acknowledgments after every IP packet
   2. B. Routing updates before sending frames
   3. C. The link while a device transmits
   4. D. ARP entries after each retransmission

   Answer: C

   Explanation: The Ethernet documentation describes "link monitoring while the devices are transmitting data." Collision detection observes the shared medium during transmission; it is not an IP acknowledgment, routing-update, or ARP-cache mechanism.

   Reference: Configure Ethernet Interfaces — Collisions and Detection

9. 9Which Junos component processes routing protocol updates and performs system management?

   1. A. An Ethernet PHY
   2. B. An egress interface queue
   3. C. The Packet Forwarding Engine
   4. D. The Routing Engine

   Answer: D

   Explanation: The Routing Engine section assigns "routing updates" and system management to the RE. The PFE handles the hardware forwarding path; physical transceivers and egress queues do not calculate routing protocol state.

   Reference: Junos OS Architecture Overview — Routing Engine, opening paragraph

10. 10From the Junos operational-mode prompt, which command enters configuration mode?

    1. A. configure
    2. B. commit
    3. C. rollback
    4. D. run

    Answer: A

    Explanation: The tour specifies "configure" to enter configuration mode. Commit activates candidate changes, rollback loads a saved configuration, and run invokes an operational command from configuration mode.

    Reference: Getting Started: A Quick Tour of the CLI — Switch Between Operational Mode and Configuration Mode, step 2