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Junos, Associate (JNCIA-Junos) Free Sample Questions

Description

Covers fundamental networking elements, core elements of the Junos OS, the Junos user interface, configuring Junos devices, monitoring and maintaining devices, and routing policy and firewall filters.

12 free sample questions150 in the full practice test Other versions: JN0-103(92),JN0-105(118)

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JN0-106 Sample Questions

  1. Question 1

    Beginner

    Networking Fundamentals · Collision domains and broadcast domains

    A network administrator is designing a new LAN topology for a branch office. They are deploying a 24-port Layer 2 Ethernet switch to connect workstations and a single router to connect the branch to the corporate WAN. How many broadcast domains and collision domains exist in this specific topology assuming all 24 switch ports are connected to active workstations and one port connects to the router?

    Answer and explanation

    Correct answer: C

    A Layer 2 switch creates a single broadcast domain for all connected devices (unless VLANs are configured) but isolates collision domains per port. With 24 workstations and 1 router connected to the switch, there are 25 active switch ports, resulting in 25 separate collision domains operating within 1 broadcast domain.

  2. Question 2

    Advanced

    Networking Fundamentals · Subnetting and supernetting

    A corporate enterprise has been allocated the IPv4 network block 192.168.10.0/24. The network engineering team must segment this block to support six new departments.

    Each department must have its own dedicated subnet. The largest department has 25 host devices that require IP addresses, while the others have fewer. The engineering team wants to use a single fixed-length subnet mask (FLSM) for all departments to simplify routing and management.

    Which subnet mask should the team apply to meet the requirements while minimizing wasted IP addresses, and how many usable hosts will be available per subnet?

    graph TD A[192.168.10.0/24] --> B[Subnet 1: .0/?] A --> C[Subnet 2: .32/?] A --> D[Subnet 3: .64/?] A --> E[Subnet 4: .96/?] A --> F[Subnet 5: .128/?] A --> G[Subnet 6: .160/?]
    Answer and explanation

    Correct answer: B

    To support 25 hosts, the subnet needs at least 5 host bits (2^5 - 2 = 30 usable hosts). A /27 mask provides 5 host bits and 3 subnet bits (from the /24 boundary). 3 subnet bits allow for 2^3 = 8 subnets, which satisfies the requirement for 6 subnets. Therefore, /27 is the optimal choice.

  3. Question 3

    IntermediateMultiple answers

    Networking Fundamentals · Layer 2 addressing, including address resolution

    When a host on an Ethernet network needs to send data to another host on the same local subnet but only knows the destination's IPv4 address, which TWO of the following statements accurately describe the address resolution process? (Select TWO)

    Answer and explanation

    Correct answers: A, C

    Address Resolution Protocol (ARP) is used to map an IP address to a MAC address. The requesting host sends an ARP request to the broadcast MAC address (FF:FF:FF:FF:FF:FF) so all devices on the local segment process it.

    When the target device receives the broadcast ARP request and recognizes its own IP address, it sends an ARP reply back to the requester. This reply is sent as a unicast frame directly to the requester's MAC address.

  4. Question 4

    Intermediate

    Networking Fundamentals · Longest match routing

    A Junos device receives a packet destined for the IP address 10.1.5.50. The routing table contains multiple active routes that encompass this destination. Based on the longest match routing principle, which of the following routes will the router select to forward the packet?

    Answer and explanation

    Correct answer: C

    Routers use the longest prefix match algorithm to select the best route among overlapping subnets. The route with the longest subnet mask (highest number of network bits) is the most specific. Among /8, /16, /24, and /0, the /24 route is the most specific match for 10.1.5.50.

  5. Question 5

    Beginner

    Networking Fundamentals · Connection-oriented vs. connectionless protocols

    True or False: Transmission Control Protocol (TCP) is an example of a connectionless protocol because it relies on the underlying IP layer to establish the path before data transmission begins.

    Answer and explanation

    Correct answer: B

    False. TCP is a connection-oriented protocol because it establishes a logical connection (via the 3-way handshake) before sending data, ensuring reliability and ordered delivery. UDP, in contrast, is a connectionless protocol.

  6. Question 6

    Beginner

    Networking Fundamentals · Decimal to binary conversion

    During a network assessment, you need to configure an interface with an IP address that ends with the decimal value 192 in the last octet. What is the correct binary representation of the decimal number 192?

    Answer and explanation

    Correct answer: C

    In binary, the octet places represent 128, 64, 32, 16, 8, 4, 2, 1. To get 192, you add 128 + 64. Therefore, the first two bits are 1s, and the remaining six bits are 0s, resulting in 11000000.

    pie title Decimal 192 Binary Breakdown "128 bit (1)" : 128 "64 bit (1)" : 64 "Remaining 6 bits (0s)" : 0

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