View Full Juniper JN0-106 Exam Dumps and Practice Test Dumps.

 

Question 381

Which Junos command is used to display routes currently present in the routing table?

1. show route
2. show routing
3. show ip route
4. show route table

Correct Answer: 1

Explanation

The show route command is one of the primary operational commands used to examine the Junos routing table. It displays routes known to the device, including directly connected, static, and dynamically learned routes. Administrators can use this information to determine whether a destination has a valid route and which protocol contributed that route. Additional options can provide more detailed information about specific routes or routing tables. Reviewing the routing table is an important troubleshooting step when connectivity problems occur because it helps determine whether the device has an appropriate path toward the destination.

Question 382

Which protocol uses a link-state database to calculate shortest paths within an autonomous system?

1. BGP
2. OSPF
3. DHCP
4. SNMP

Correct Answer: 2

Explanation

OSPF is a link-state routing protocol that maintains a link-state database describing the network topology within an OSPF area. Routers exchange link-state information and use the collected information to calculate shortest paths. The Shortest Path First algorithm is then used to determine appropriate routes. BGP operates as a path-vector protocol, while DHCP provides address configuration and SNMP is used for network management. Understanding OSPF’s link-state operation is important when troubleshooting routing relationships, neighbor formation, route calculation, and database synchronization between OSPF routers.

Question 383

Which IPv4 address is reserved for loopback testing?

1. 192.168.1.1
2. 169.254.1.1
3. 127.0.0.1
4. 10.0.0.1

Correct Answer: 3

Explanation

The IPv4 address 127.0.0.1 is the commonly used loopback address for testing the local TCP/IP stack. Traffic sent to this address remains within the local device and does not need to travel through a physical network interface. Loopback testing can help determine whether local IP functionality is operating correctly. The 10.0.0.0/8 range is private address space, 192.168.0.0/16 is also private, and 169.254.0.0/16 is associated with IPv4 link-local addressing. Recognizing special IPv4 ranges helps administrators interpret addressing and troubleshoot connectivity problems.

Question 384

Which Junos command displays a comparison between the candidate configuration and the active configuration?

1. show configuration compare
2. show | compare
3. compare configuration
4. show changes

Correct Answer: 2

Explanation

The show | compare command is used in Junos configuration mode to display differences between the candidate configuration and the currently committed configuration. This is especially useful before committing changes because administrators can review exactly what has been added, modified, or deleted. Reviewing differences helps identify accidental configuration changes and provides an additional verification step before activation. Junos uses a candidate configuration model, so changes can be prepared and examined without immediately affecting the active configuration. Administrators commonly use show | compare together with commit check before completing a configuration change.

Question 385

Which BGP attribute is commonly used to prefer one exit path over another within an autonomous system?

1. AS Path
2. MED
3. Local Preference
4. Origin

Correct Answer: 3

Explanation

Local Preference is a BGP attribute commonly used to influence the preferred outbound path within an autonomous system. A higher local preference is generally preferred when comparing otherwise applicable BGP routes. Because the value is propagated within the autonomous system, it can help coordinate which exit point routers should use for external destinations. AS Path, MED, and Origin are other BGP attributes used during route selection for different purposes. Understanding local preference is important when troubleshooting why internal routers choose one external path instead of another.

Question 386

Which Junos command provides detailed information about a specific interface?

1. show interfaces terse
2. show interfaces detail
3. show interface status
4. show port information

Correct Answer: 2

Explanation

The show interfaces detail command provides more detailed information about interfaces than the terse form. It can display operational characteristics, configuration-related information, statistics, and other interface details depending on the platform and interface type. Administrators can use this information when investigating interface problems that are not clear from a basic status summary. The terse command is useful for quickly checking many interfaces, while detailed output is more appropriate for focused troubleshooting. When investigating connectivity, interface information can be considered together with routing, ARP or NDP, logs, and protocol status.

Question 387

Which Junos command checks whether the candidate configuration is syntactically valid before committing it?

1. commit check
2. validate configuration
3. check commit
4. test configuration

Correct Answer: 1

Explanation

The commit check command validates the candidate configuration without actually activating the changes. It can identify configuration problems that would prevent a successful commit. This makes it useful before committing changes to a production device. Administrators can first make changes, review them with show | compare, and then run commit check. If validation succeeds, the configuration can normally proceed to a regular commit. This workflow reduces the risk of introducing invalid configuration statements. It is especially useful when several related configuration changes have been made in different parts of the hierarchy.

Question 388

Which IPv6 address range is used for link-local addresses?

1. 2000::/3
2. FC00::/7
3. FF00::/8
4. FE80::/10

Correct Answer: 4

Explanation

The IPv6 FE80::/10 range is reserved for link-local addresses. Link-local addresses are used for communication on the local network segment and are not normally routed between different links. IPv6-enabled interfaces commonly use link-local addresses for Neighbor Discovery and other local communication functions. The 2000::/3 range is associated with global unicast addresses, FC00::/7 is used for unique local addressing, and FF00::/8 is used for multicast. Recognizing these address ranges is important when configuring and troubleshooting IPv6 networks.

Question 389

Which Junos command displays the configured system hostname?

1. show hostname
2. show system host-name
3. show configuration system host-name
4. show host

Correct Answer: 3

Explanation

The system hostname is configured within the system hierarchy of the Junos configuration. The command show configuration system host-name can be used to display the configured hostname statement. The hostname helps identify a device during administration, logging, and network management. Administrators commonly configure unique hostnames so that routers and switches can be easily distinguished. When troubleshooting a device, verifying the hostname can also help ensure that configuration or operational commands are being performed on the intended system. The hostname configuration is separate from interface addresses and routing protocol configuration.

Question 390

Which protocol is commonly used to securely transfer files between network devices?

1. FTP
2. SCP
3. TFTP
4. Telnet

Correct Answer: 2

Explanation

Secure Copy Protocol, or SCP, provides a secure method for transferring files between systems using encrypted communication. It is commonly used for transferring configuration files, software images, logs, or other administrative files when supported by the device and environment. FTP and TFTP do not provide the same level of secure encrypted transport, while Telnet is primarily a remote-access protocol and does not provide secure file transfer. SCP is particularly useful in network administration because it combines file transfer with the security mechanisms provided by SSH.

Question 391

Which Layer 2 technology allows multiple VLANs to traverse a single Ethernet link?

1. Access mode
2. 802.1Q trunking
3. STP
4. ARP

Correct Answer: 2

Explanation

IEEE 802.1Q trunking allows multiple VLANs to traverse a single Ethernet link by using VLAN tags in Ethernet frames. A trunk interface can carry traffic belonging to multiple VLANs between switches or between other VLAN-aware devices. An access interface normally carries traffic for a single VLAN. STP is used to prevent Layer 2 loops, while ARP is used for IPv4 address resolution. Understanding the difference between access and trunk interfaces is important when configuring VLAN connectivity and troubleshooting situations where devices in different parts of a switched network cannot communicate as expected.

Question 392

Which Junos command displays the ARP table for IPv4 neighbors?

1. show arp
2. show ipv4 arp
3. show neighbors
4. show ethernet arp

Correct Answer: 1

Explanation

The show arp command displays Address Resolution Protocol information on a Junos device. The ARP table maps IPv4 addresses to corresponding Layer 2 MAC addresses for reachable neighbors on local networks. This information is useful when troubleshooting IPv4 connectivity because it can show whether the device has successfully resolved a neighbor’s address. If an expected ARP entry is missing, administrators may investigate interface status, VLAN configuration, addressing, and local connectivity. IPv6 uses Neighbor Discovery rather than ARP, so IPv6 neighbor information is examined with NDP-related commands.

Question 393

Which Junos configuration mode is entered by using the configure command?

1. Monitoring mode
2. Shell mode
3. Configuration mode
4. Diagnostic mode

Correct Answer: 3

Explanation

The configure command moves an administrator from Junos operational mode into configuration mode. In configuration mode, administrators can create, modify, or delete configuration statements. Changes are initially stored in the candidate configuration and normally require a successful commit before becoming active. Configuration mode provides a hierarchical structure for organizing system, interface, routing, security, and protocol settings. Administrators can use commands such as set, delete, edit, up, and top to navigate and modify the configuration. Understanding the distinction between operational and configuration modes is fundamental to Junos administration.

Question 394

Which protocol is commonly used to automatically provide IP configuration information to clients?

1. NTP
2. DHCP
3. SNMP
4. BGP

Correct Answer: 2

Explanation

Dynamic Host Configuration Protocol, or DHCP, can automatically provide clients with network configuration information such as an IP address, subnet mask, default gateway, and DNS server information. This reduces the need to manually configure every client. DHCP operates through a client-server model and can provide address leases for defined periods. NTP synchronizes time, SNMP provides monitoring and management, and BGP exchanges routing information. In network environments, DHCP is commonly used for endpoint addressing while routers and switches may use static or dynamically configured addresses depending on the network design.

Question 395

Which Junos command displays messages recorded in the system log?

1. show system log
2. show log messages
3. show messages
4. show system messages

Correct Answer: 4

Explanation

The show system messages command is used to display the contents of the system messages log on Junos devices. System logs can contain information about interface events, system processes, authentication activity, configuration operations, and other events. Log messages are valuable when troubleshooting because they provide a historical record that can be correlated with observed network behavior. Administrators can also configure additional logging destinations and files depending on operational requirements. When investigating a problem, reviewing relevant log entries together with interface, routing, and protocol information can help establish when an issue occurred and what systems were involved.

Question 396

Which routing protocol is commonly used to exchange routing information between autonomous systems?

1. OSPF
2. RIP
3. BGP
4. STP

Correct Answer: 3

Explanation

Border Gateway Protocol, or BGP, is designed for exchanging routing information between autonomous systems. It is therefore fundamental to interdomain routing and is widely used between service providers, enterprises, and other independently administered networks. BGP uses attributes such as AS Path and Local Preference to support route selection and policy control. OSPF and RIP are generally used as interior routing protocols, while STP operates at Layer 2 rather than exchanging IP routes. BGP troubleshooting commonly involves checking peer sessions, route advertisements, received routes, and routing policies.

Question 397

Which Junos command can be used to safely test a configuration change for a limited period before automatic rollback?

1. commit confirmed
2. commit temporary
3. commit rollback
4. commit test

Correct Answer: 1

Explanation

The commit confirmed command allows administrators to activate configuration changes while specifying a confirmation period. If the administrator does not confirm the commit within that period, Junos can automatically roll back to the previous committed configuration. This feature is particularly useful when making remote changes that could potentially interrupt management access. If the configuration causes connectivity to be lost, automatic rollback can restore the previous working configuration. It provides an additional safety mechanism for remote administration. Administrators should still carefully review changes before committing and confirm the configuration when the new state has been verified.

Question 398

Which protocol prevents Layer 2 switching loops by creating a loop-free logical topology?

1. OSPF
2. STP
3. BGP
4. NTP

Correct Answer: 2

Explanation

Spanning Tree Protocol, or STP, helps prevent Layer 2 loops in switched Ethernet networks. When redundant Layer 2 paths exist, STP logically blocks selected paths so that a loop-free topology is maintained. If the active path fails, STP can allow an appropriate alternate path to become active depending on the STP implementation and configuration. OSPF and BGP are Layer 3 routing protocols, while NTP is used for time synchronization. Understanding STP is important when working with redundant switches because unmanaged Layer 2 loops can result in excessive traffic and unstable network behavior.

Question 399

Which Junos command displays information about currently logged-in users?

1. show users
2. show system users
3. show login users
4. show active users

Correct Answer: 2

Explanation

The show system users command displays information about users currently logged into the Junos device. This can help administrators determine who has active management sessions and which terminals or login methods are being used. User-session information can be valuable during maintenance and troubleshooting, especially when multiple administrators are working on the same device. Authentication configuration may involve local users or external authentication services such as RADIUS or TACACS+. Reviewing active users provides operational visibility but does not by itself show every detail of historical authentication activity, which may instead be available through appropriate logging.

Question 400

Which Junos component is primarily responsible for running routing protocols and maintaining the control plane?

1. Packet Forwarding Engine
2. Routing Engine
3. Switching Fabric
4. Interface Module

Correct Answer: 2

Explanation

The Routing Engine is responsible for major control-plane functions on a Junos device. It runs routing protocols such as OSPF and BGP, maintains routing information, handles management functions, and participates in the creation of forwarding information. The Packet Forwarding Engine is primarily responsible for high-speed packet forwarding based on the forwarding information provided by the control plane. Understanding the distinction between the Routing Engine and Packet Forwarding Engine is important for Junos troubleshooting and architecture questions. Control-plane problems generally involve the Routing Engine, while forwarding-related issues may involve the Packet Forwarding Engine.