매달, 우리는 1000명 이상의 사람들이 시험 준비를 잘하고 시험을 잘 통과할 수 있도록 도와줍니다.
Junos, Associate (JNCIA-Junos) 온라인 연습
최종 업데이트 시간: 2026년06월04일
당신은 온라인 연습 문제를 통해 Juniper JN0-106 시험지식에 대해 자신이 어떻게 알고 있는지 파악한 후 시험 참가 신청 여부를 결정할 수 있다.
시험을 100% 합격하고 시험 준비 시간을 35% 절약하기를 바라며 JN0-106 덤프 (최신 실제 시험 문제)를 사용 선택하여 현재 최신 111개의 시험 문제와 답을 포함하십시오.
정답:
Explanation:
In the Junos OS architecture, interfaces are strictly divided into physical and logical components. The physical interface represents the actual hardware port (e.g., ge-0/0/0), while logical units (e.g., ge-0/0/0.0) define the protocol-specific parameters and logical segmentation required for traffic processing. A fundamental characteristic of this model is that a single physical interface can host multiple logical units. This is a mandatory requirement for technologies such as 802.1Q VLAN tagging, where each logical unit corresponds to a different VLAN ID on the same physical link, allowing for efficient micro-segmentation of traffic.
Furthermore, Junos OS allows logical units to have multiple IP addresses assigned to them within the same address family or across different families (such as inet and inet6). This flexibility enables a single logical interface to reside on multiple subnets simultaneously, which is essential for complex routing scenarios, multi-homing, or transitional dual-stack environments. It is a common misconception that logical units are reserved for management; in reality, every physical interface must have at least one logical unit (typically unit 0) configured for the device to process any transit or local traffic. Understanding the hierarchical relationship between the physical port and its logical subdivisions is critical for successful interface management and protocol deployment on Junos platforms. Junos OS Fundamentals, Interface Naming and Hierarchy.
정답:
Explanation:
The provided exhibit displays the output of the show route table inet6.0 command, which represents the master routing table for IPv6 unicast traffic in Junos OS. Analysis of the specific route entries reveals that all listed destinations are categorized as either [Direct/0] or [Local/0]. These route types indicate that the table only contains networks physically connected to the router's interfaces and the specific IP addresses assigned to those interfaces.
Because there are no routes identified by dynamic protocols (such as OSPFv3, IS-IS, or BGP) or static entries, it is verified that the router is not learning IPv6 routes from any neighbors or peers. Consequently, the routing table lacks reachability information for any non-local or remote IPv6 segments. Without these routes or a configured default gateway (::/0), the router is unable to forward traffic to remote IPv6 networks. Statements C and D are factually incorrect based on the exhibit: the 2001:db8:22:108::/64 network is associated with interface ge-0/0/4.0 (not ge-0/0/5.0), and the 2001:db8:22:107::/64 network is entirely absent from the displayed routing table.
정답:
Explanation:
In Junos OS, the configuration database is designed with a robust versioning system that facilitates rapid recovery from administrative errors. Every time a commit command is successfully executed, the system automatically archives the previous active configuration and assigns it a "rollback" index. The rollback command is used within configuration mode to revert the candidate configuration to a previously saved state.
The indices are zero-based, where rollback 0 represents the currently active configuration that was just committed. To restore the configuration that was functional immediately before the most recent, problematic commit, the administrator must use rollback 1. This command replaces the current candidate configuration with the contents of the last known working state. It is important to note that executing rollback 1 only populates the candidate buffer; to make this previous configuration active and restore connectivity, the administrator must subsequently issue the commit command. This mechanism is a cornerstone of Junos OS's commitment to high availability and operational resilience, allowing for nearly instantaneous restoration of services without the need for manual line-by-line configuration edits during a network outage.
정답:
Explanation:
In the Junos OS architecture, the authentication-order statement within the [edit system] hierarchy defines the sequence in which the device attempts to validate user credentials against external and internal databases. The order specified in the exhibit is [ radius tacplus password ], meaning the device first queries the RADIUS server, followed by the TACACS+ server, and finally the local password database.
A critical distinction in Junos authentication logic is the difference between a server being "unavailable" and a server "rejecting" a user. If an authentication server responds with an explicit access-reject (meaning it received the request but the credentials were invalid), the authentication process terminates immediately to maintain security integrity. However, if the server is unreachable or fails to respond within the configured timeout period (unavailable), the Junos Control Plane automatically falls back to the next method in the defined sequence. In this specific scenario, since the RADIUS server is unavailable, the device will proceed to attempt authentication using the TACACS+ server. If that were also unavailable, it would finally check the local password database. This fallback mechanism ensures that administrators can still access the device even during external server outages, provided they have a local account configured as the final method in the list.
정답:
Explanation:
To effectively troubleshoot packet forwarding in a Junos environment, an architect must distinguish between the control plane's Routing Information Base (RIB) and the data plane's Forwarding Information Base (FIB). While the command show route displays the RIB (the master routing table maintained by the Routing Engine), it does not necessarily reflect the actual instructions being executed by the hardware. The definitive command for viewing the data plane's active path selection is show route forwarding-table.
Executing this command reveals the contents of the FIB as it has been pushed from the Routing Engine to the Packet Forwarding Engine (PFE). The output provides critical diagnostic data, including the destination prefix, the specific next-hop IP address, the interface through which the packet will egress, and the type of route (such as unicast or broadcast). This is the "ground truth" for packet movement; if a route exists in the RIB but is missing from the forwarding table, it indicates a failure in the communication between the RE and PFE. Utilizing this command is the primary method for identifying black holes, incorrect next-hop resolution, or issues with hardware-level filter applications that might be impacting transit traffic flow at wire speed.
정답:
Explanation:
In the Junos OS architecture, configuration groups (defined under the [edit groups] hierarchy) provide a powerful mechanism for template-based management. This approach is specifically designed to handle scenarios where multiple configuration objects, such as twenty different Ethernet interfaces, require identical parameters like a specific description or MTU value. By defining these common settings once within a group, an administrator can then apply that group to multiple interfaces using the apply-groups statement.
This methodology drastically reduces the number of repetitive commands required and, more importantly, ensures strict consistency across the device. If the MTU needs to be adjusted in the future, the change is made in a single location―within the configuration group―and is automatically inherited by all interfaces to which the group is applied. This inheritance model prevents "configuration drift" where individual interfaces might otherwise end up with mismatched settings due to manual entry errors. Using configuration groups is considered a best practice for Senior Architects managing high-density platforms, as it simplifies the candidate configuration file and makes the management of bulk interface settings both scalable and error-resistant.
정답:
Explanation:
In the Junos OS architecture, the Routing Engine (RE) manages path selection by evaluating multiple potential routes to a specific destination found within the Routing Information Base (RIB). When multiple routing sources (such as static configuration, OSPF, IS-IS, and BGP) provide information for the exact same destination prefix―in this case, 192.168.100.100/32―the device utilizes route preference as the primary tie-breaker to determine which entry becomes the "active" route.
The provided exhibit displays the default preference values for each protocol: Static is 5, OSPF is 10, IS-IS is 15, and BGP is 170. Junos OS follows a "lower is better" logic for preference; therefore, the Static route is selected as the most trustworthy path. In the command output, the active route is explicitly identified by the asterisk (*) and plus sign (+) symbols located next to the [Static/5] entry. Looking at the specific next-hop information for this active static route, the output indicates the traffic is sent to 192.168.0.2 via xe-0/0/0.0. Consequently, the Packet Forwarding Engine (PFE) will install this specific path into the forwarding table, causing all traffic destined for 192.168.100.100 to be egressed over the xe-0/0/0.0 interface.
정답:
Explanation:
In Junos OS, the Packet Forwarding Engine (PFE) determines the next hop for a packet by performing a lookup in the forwarding table and identifying all valid matches for the destination IP address. When multiple routes encompass the same destination, the router strictly follows the Longest Prefix Match (LPM) rule to select the most specific entry.
For the destination address 10.0.0.9, the following evaluation occurs based on the exhibit:
정답:
Explanation:
Junos OS features a sophisticated configuration management system that automatically creates a snapshot of the active configuration every time a commit is successfully performed. These snapshots are stored as rollback files in a historical archive. Within the configuration mode hierarchy, the rollback command allows an administrator to discard current candidate changes and load a previously committed configuration into the candidate buffer.
The numbering of these rollback files is sequential and follows a specific logic: rollback 0 represents the configuration that is currently active and running on the system. To revert to the state that existed immediately prior to the most recent commit, the administrator must use rollback 1. This command overwrites the current candidate configuration with the previous operational state. It is important to note that executing rollback 1 does not immediately impact the running system; it merely populates the candidate database. The changes must still be verified―often using show | compare―and then finalized by executing the commit command. By default, Junos maintains up to 50 of these rollback configurations (and up to 100 on certain platforms/versions), providing a robust safety net for operational recovery and auditing. Configuration Basics, Managing Configurations, Rollback configurations.
정답:
Explanation:
The architecture of Junos OS is designed with a strict functional separation between the control plane and the data plane. The Routing Engine (RE) maintains the master Routing Information Base (RIB), which acts as a comprehensive database storing all potential paths learned from various routing protocols, static configurations, and direct connections. However, to achieve wire-speed performance, the device does not consult the RIB for every packet. Instead, the RE identifies the "active" or best routes for each destination based on route preference and metrics.
Once these active routes are selected, the RE distills them into a streamlined Forwarding Information Base (FIB), commonly referred to as the forwarding table, and pushes this table to the Packet Forwarding Engine (PFE). The main function of the forwarding table is to provide a high-speed, local lookup mechanism that allows the PFE to forward transit traffic across the switch fabric with minimal latency. This table contains only the specific exit interface and Layer 2 next-hop information required for packet delivery. By isolating the PFE from the overhead of complex routing protocol state machines and all inactive redundant paths, Junos OS ensures that forwarding performance remains consistent even during control plane re-convergence. Junos OS Fundamentals, Control Plane and Forwarding Plane functions.
정답:
Explanation:
Analyzing the provided exhibit of the inet.0 routing table reveals that the destination network 10.0.0.0/24 currently has two viable paths: a static route with a preference of 5 and an OSPF route with a preference of 10. Both routes are configured to use 10.12.0.1 via the ge-0/0/1.0 interface as their primary next hop. The static route is currently marked with an asterisk (*), indicating it is the active path chosen by the Routing Engine due to its lower preference value.
In the event that the ge-0/0/1 interface transitions to a "down" state, the physical layer failure triggers the immediate invalidation of all routes associated with that link. Consequently, both the specific static and OSPF routes for the 10.0.0.0/24 prefix are purged from the active forwarding table. The Routing Engine must then perform a re-evaluation of the routing table to identify the next best match for any traffic destined for that range. Since there are no other more specific or equally specific routes available for the 10.0.0.0/24 network, the router falls back to the default route (0.0.0.0/0). As shown in the exhibit, the default route points to the next-hop address 10.23.0.3 via interface ge-0/0/2.0. Therefore, if the primary interface fails, traffic will be redirected through this secondary gateway.
정답:
Explanation:
In Junos OS, routing information is meticulously organized into separate databases known as routing tables, each identified by a specific name corresponding to an address family and its intended operational purpose. The master routing table for IPv4 unicast information is inet.0. For the IPv6 address family, Junos OS utilizes inet6.0 as the default master routing table for all unicast reachability information. This table stores all IPv6 prefixes learned from directly connected interfaces, static configurations, and dynamic routing protocols such as OSPFv3, IS-IS, or BGP.
It is a core architectural principle in Junos to isolate these families to ensure management clarity and prevent address space collisions. While the system utilizes other specialized tables for specific functions―such as inet.3 for MPLS path information or inet.1 for multicast forwarding caches―inet6.0 remains the primary repository for IPv6-based forwarding decisions. When a Junos device receives an IPv6 packet, the Packet Forwarding Engine (PFE) performs a lookup against the entries derived from this table to determine the appropriate egress interface and next-hop address. Understanding this default table structure is essential for network architects when troubleshooting dual-stack environments or configuring protocol-specific import and export policies.
정답:
Explanation:
In the Junos OS architecture, maintaining a reliable recovery point is a critical post-installation task. While the system automatically archives previous configurations as "rollback" files every time a commit is performed, these files are transient and can eventually be rotated out of the default 50-file history as new changes are made. To ensure a permanent and reliable recovery state, a Senior Architect should manually create a rescue configuration.
The rescue configuration is a specifically designated file used to restore a device to a known-working state if it becomes unreachable or the configuration becomes corrupted. Unlike standard rollbacks, the rescue configuration is only created or updated when an administrator explicitly issues the operational mode command request system configuration rescue save. This ensures that even if several subsequent commits flush the desired initial state from the standard rollback archive, the "safe harbor" configuration remains intact on the storage media. This state can then be re-activated via the rollback rescue command in configuration mode followed by a commit. Setting a rescue configuration after the initial setup is a foundational best practice for disaster recovery and operational stability, providing a "last resort" configuration that is immune to the automated rotation of the commit history.
정답:
Explanation:
In Junos OS, the rescue configuration is a specifically designated file that stores a known-working configuration, intended to be used for emergency recovery when the device becomes unreachable or unstable due to recent changes. This configuration is not created automatically; an administrator must proactively save a stable state using the operational mode command request system configuration rescue save. This differs from the standard rollback archive, which automatically stores up to 50 previous configurations but can eventually rotate out the specific "last known good" state needed for recovery.
When a device loses network connectivity, console access becomes the only viable management path. To restore the rescue configuration, the administrator must enter configuration mode using the configure command. Once inside the candidate configuration buffer, the rollback rescue command is issued. This command directs the Junos OS to locate the designated rescue file and load its contents over the current candidate configuration. Upon receiving the "load complete" confirmation, the administrator must execute a commit to promote the candidate configuration to the active, running state. Sequence C correctly follows this logic. Sequence A is technically incorrect for standard rescue restoration as load override typically targets specific file paths or URLs, whereas rollback rescue is the built-in mechanism for this function. Sequences B and D are destructive or counter-productive, either deleting the rescue file or overwriting it with the current, non-functional configuration state. Operational Monitoring and Maintenance, Configuration Recovery, Rescue Configuration.
정답:
Explanation:
When a Junos device is initialized for the first time or after a factory reset, it operates with a "factory-default" configuration. This configuration contains the minimum settings necessary for the device to boot, but it lacks essential security parameters. The Junos OS kernel enforces a strict security mechanism that prevents any administrator from successfully executing a commit command until a root-level password has been defined.
Specifically, the root-authentication object must be configured under the [edit system] hierarchy. This requirement ensures that no Junos device is deployed into a production environment with an open, unauthenticated root account. If an administrator attempts to commit changes without this setting, the configuration parser will return a "missing mandatory statement" error and the commit process will fail. While other settings―such as a system hostname, management IP address (on the fxp0 or me0 interfaces), or logical interface configurations―are critical for operational readiness, they are not strictly enforced by the system validation logic for the initial activation. Only the root-authentication (which can be a plain-text password or an encrypted key) is a hard prerequisite for transitioning the device from a default state to an active, running configuration.