JN0-106 Practice Test 14 — 15 Questions

Question 1

An engineer is designing a network and needs to ensure that management traffic (SSH, SNMP) is always permitted, even if an interface firewall filter is applied. Which Juniper best practice should be followed?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Apply a firewall filter on the loopback interface (lo0) to protect the device. Applying a firewall filter to the loopback interface (lo0) is the Juniper best practice for protecting management traffic because the loopback interface is the logical termination point for all control plane traffic, including SSH and SNMP. This ensures that management traffic is always permitted regardless of which physical interface it arrives on, while still allowing interface-specific filters to be applied for data plane traffic without risk of blocking management access.

Answer

Use a firewall filter that permits all management traffic at the top of the list on each interface

Answer

Apply a firewall filter to the management interface (fxp0)

Answer

Disable the firewall filter on all interfaces

Question 2

Refer to the exhibit. The route for 192.168.0.0/16 is hidden. What is the most likely reason?

Accepted Answer

The BGP next-hop is unreachable. In JUNOS, a BGP route is hidden when the next-hop address is not reachable via any active route in the routing table. The router cannot install the route into the forwarding table because it lacks a valid path to the next-hop, causing the route to be marked as hidden. This is a common issue when the next-hop is not covered by a directly connected or static route, or when the IGP route to the next-hop is missing.

Answer

The route has a lower local preference

Answer

The route has a longer AS path

Answer

The route has a higher MED value

Question 3

You are a junior network engineer tasked with upgrading the Junos OS on a pair of EX3400 switches that are in a Virtual Chassis. You have downloaded the new software image to the primary switch. Before performing the upgrade, you must verify the image's integrity and check the current version. Which sequence of commands should you use?

Accepted Answer

Run 'show version' and then 'request system software validate /var/tmp/junos-new.tgz'.. 'show version' displays the current Junos OS version running on the switch, which is necessary to confirm the starting point before an upgrade. Then 'request system software validate /var/tmp/junos-new.tgz' performs a checksum verification and package integrity check on the image file without installing it, ensuring the image is not corrupted. This sequence directly addresses the two tasks: verifying the image's integrity and checking the current version.

Answer

Run 'show system uptime' and then 'request system software add /var/tmp/junos-new.tgz'.

Answer

Run 'show system software' and then 'request system software add validate'.

Answer

Run 'show configuration system software' and then 'file checksum sha256 /var/tmp/junos-new.tgz'.

Question 4

A network administrator is configuring a new subnet for servers that must not communicate with each other directly but must be able to reach a default gateway. Which type of route should be configured on the servers?

Accepted Answer

Default route pointing to the gateway. A default route (0.0.0.0/0) pointing to the gateway is correct because it allows servers to reach any external destination (including the gateway) without requiring explicit routes to each other. Since the servers must not communicate directly, they should not have routes to each other's subnets; the default route ensures all non-local traffic is forwarded to the gateway, which can then enforce isolation policies.

Answer

Host route for the gateway

Answer

Dynamic route via OSPF

Answer

Static route to each other server

Question 5

You are a network administrator for a service provider that uses Juniper MX series routers to provide MPLS VPN services to customers. Management has requested that you implement a secure out-of-band management (OOBM) solution for all MX routers to ensure that management traffic is isolated from the production network, reducing the risk of unauthorized access and management plane attacks. You are tasked with designing the OOBM solution using a dedicated management interface (me0) and a separate management routing instance. Which of the following best practices should you follow?

Accepted Answer

Create a dedicated routing instance for management, assign me0 to it, and apply a firewall filter to restrict access. It follows Juniper's best practice for OOBM: creating a dedicated management routing instance (e.g., mgmt_junos) and assigning the me0 interface to it. This ensures management traffic is completely isolated from the production routing table (inet.0), preventing management plane attacks and unauthorized access. Applying a firewall filter on the me0 interface further restricts access to only authorized management hosts, aligning with security hardening guidelines.

Answer

Place me0 in the inet.0 routing table and rely on static routes

Answer

Enable VLAN tagging on me0 to separate management traffic into different subnets

Answer

Configure the me0 interface in the default routing instance with a simple ACL

Question 6

An engineer needs to apply a configuration change to the Junos device that must survive a reboot. Which configuration mode command should be used to save the changes?

Accepted Answer

commit. The 'commit' command is the standard way to apply a candidate configuration to the active configuration in Junos. When you issue 'commit', the changes are saved to the /config/juniper.conf.gz file, which is loaded upon reboot, ensuring the configuration survives a restart.

Answer

commit confirmed

Answer

commit synchronize

Answer

commit check

Question 7

Which TWO statements about route preferences in Junos are correct?

Accepted Answer

Direct routes have a default preference of 0.. In Junos, direct (connected) routes have a default route preference of 0, which is the highest possible preference, ensuring they are always preferred over other route types for directly attached networks. Option C is correct because OSPF internal routes (both intra-area and inter-area) have a default preference of 10 in Junos, which is lower than most other dynamic routing protocols, making OSPF routes more preferred by default.

Answer

The preference of a route cannot be changed.

Answer

Static routes have a default preference of 10.

Answer

BGP routes have a default preference of 200.

Question 8

Refer to the exhibit. What does the 'user' type indicate about the route?

Accepted Answer

The route was manually configured.. In Junos, the 'user' type in a route table indicates that the route was manually configured, typically via a static route statement under the 'routing-options' hierarchy. This distinguishes it from routes learned dynamically through routing protocols or derived from the kernel's interface addresses.

Answer

The route is from the kernel.

Answer

The route is a default route generated by the router.

Answer

The route was learned from a routing protocol.

Question 9

Your company runs a Juniper MX480 router as the core gateway. The router has been experiencing intermittent connectivity issues with a remote site over a point-to-point OC3 link. Users report that the link goes down for a few seconds several times a day. You suspect that the issue might be related to physical layer errors or framing. You need to determine the cause and collect relevant data to present to the service provider. Which course of action should you take first?

Accepted Answer

Run 'monitor interface so-0/0/0' and observe for any CRC errors or alarms over a period of time.. 'monitor interface so-0/0/0' provides real-time, continuous display of interface counters and alarms, allowing you to observe CRC errors, framing errors, or alarms (e.g., LOS, LOF) as they occur. This is the most direct way to capture transient physical-layer issues on a SONET/SDH OC3 link without disrupting service, making it the appropriate first step before escalating to the service provider.

Answer

Perform a loopback test on the interface using 'test interface so-0/0/0'.

Answer

Review the system syslog file using 'show log messages' and search for interface down messages.

Answer

Immediately replace the serial interface card to rule out hardware failure.

Question 10

A network administrator makes several changes to the configuration but decides to discard all uncommitted changes and start fresh. Which command should be used to revert the candidate configuration back to the current active configuration?

Accepted Answer

rollback 0. The 'rollback 0' command reverts the candidate configuration to the currently active configuration, discarding all uncommitted changes. This is because Junos maintains a rollback database of the last 50 committed configurations, with index 0 always representing the active configuration. Using 'rollback 0' effectively resets the candidate configuration to match the active one, allowing the administrator to start fresh without affecting the running system.

Answer

load override

Answer

commit check

Answer

rollback 1

Question 11

A company is deploying an EVPN-VXLAN fabric with Juniper QFX switches. To provide inter-subnet routing, which interface type must be configured?

Accepted Answer

IRB interface. In an EVPN-VXLAN fabric, Integrated Routing and Bridging (IRB) interfaces are required to provide inter-subnet routing. IRB interfaces act as Layer 3 gateways within the VXLAN overlay, enabling routing between different VLANs/VXLANs by terminating both the bridge domain and the routing instance. Without IRB, traffic cannot be routed between subnets in the EVPN-VXLAN fabric.

Answer

Physical interface with vlan-tagging

Answer

VXLAN tunnel endpoint (VTEP)

Answer

Loopback interface

Question 12

A network operations team has received a new Juniper router to replace an existing legacy router. The team needs to apply a baseline configuration that includes system settings, interfaces, and security policies. The configuration is provided as a text file containing Junos configuration hierarchy syntax (e.g., 'system { host-name... }'). The engineer connects to the console and sees the prompt 'root@%'. What is the most efficient way to apply the configuration?

Accepted Answer

Use the 'load merge' command to merge the configuration file.. The engineer is at the shell prompt (root@%), not in configuration mode. The 'load merge' command is used within configuration mode to merge a configuration file (in Junos hierarchy syntax) into the candidate configuration, which is the most efficient way to apply a pre-written baseline configuration without manual typing or complex file transfers.

Answer

Use the 'load set' command to load a set of configuration commands.

Answer

Use FTP to transfer the file and then commit.

Answer

Enter configuration mode and manually type each command.

Question 13

An engineer needs to view the current active configuration of a Junos device without making any changes. Which CLI mode should they use?

Accepted Answer

Operational mode. Operational mode is the default CLI mode in Junos, used for monitoring, troubleshooting, and viewing the current active configuration without making any changes. Commands in this mode are read-only and do not modify the device's configuration. The active configuration is the one currently running on the device, and it can be viewed using commands like 'show configuration' in operational mode.

Answer

Privileged mode

Answer

Configuration mode

Answer

Exclusive configuration mode

Question 14

In a dual Routing Engine (RE) setup, an engineer commits a configuration change that should be applied to both REs synchronously. What is the correct command to ensure both REs receive the same configuration immediately?

Accepted Answer

commit synchronize. The 'commit synchronize' command commits the configuration on the master Routing Engine and then automatically copies and commits the same configuration to the backup RE, ensuring both REs have identical active configurations immediately. This is the standard Junos method for synchronizing configurations in a dual-RE chassis.

Answer

commit confirmed

Answer

commit check synchronize

Answer

commit and-quit

Question 15

Refer to the exhibit. An administrator needs to ensure that all emergency (emerg) messages are logged to the console. Based on the configuration shown, which statement is correct?

Accepted Answer

Emergency messages are logged to all destinations.. The configuration shown includes the 'any' facility and 'emerg' severity for the console, file, and remote host destinations. In JUNOS, when a severity level is set for a syslog destination, all messages of that severity and higher are logged. Since 'emerg' is the highest severity, it applies to all configured destinations, not just one.

Answer

Emergency messages are logged to the console only.

Answer

Emergency messages are logged only to the file 'messages'.

Answer

Emergency messages are logged only to the remote host.