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Question 46: 

Which command is used to display the current active configuration on a Junos device?

A) show configuration

B) show running-config

C) display configuration

D) get configuration

Answer: A

Explanation:

The show configuration command displays the current active configuration on a Junos device, showing all configured settings organized in hierarchical format. This command reveals the configuration that is currently running on the device and controlling its behavior. The output displays configuration statements in set command format or hierarchical stanza format depending on display options.

The show configuration command can be used at any hierarchy level to display configuration at that level and below. When executed at the top level, it shows the entire configuration. When executed within a specific hierarchy like interfaces or protocols, it shows only that portion of the configuration. This flexibility allows administrators to focus on relevant configuration sections.

Additional options modify the display including show configuration | display set which shows configuration as individual set commands useful for copying, show configuration | display inheritance which includes inherited configuration, and show configuration | compare which compares candidate with active configuration. These variations provide different perspectives on configuration for various administrative tasks.

Understanding configuration display is fundamental for Junos administration as it enables verifying current settings, documenting configurations, troubleshooting issues by reviewing settings, and preparing configuration changes by understanding current state. Administrators regularly use show configuration to review device settings before making changes.

Option B is incorrect because show running-config is a Cisco IOS command, not a Junos command. While functionally similar to show configuration, Junos uses different command syntax. Administrators transitioning from Cisco to Juniper must learn the Junos command syntax and structure which differs significantly from IOS commands.

Option C is incorrect because display configuration is not a valid Junos command. While display is used as a pipe modifier with show configuration like show configuration | display set, display configuration alone is not a recognized command. Proper Junos syntax requires show configuration as the base command.

Option D is incorrect because get configuration is not a valid Junos command. While get is used in some Junos contexts, it is not the command for displaying configuration. The standard Junos command for viewing configuration is show configuration, which should be memorized as fundamental to Junos administration.

Question 47: 

What is the purpose of the commit confirmed command in Junos?

A) To automatically roll back configuration changes if not confirmed within a specified time

B) To immediately activate configuration without validation

C) To save configuration to backup storage

D) To merge configuration from multiple sources

Answer: A

Explanation:

The commit confirmed command automatically rolls back configuration changes if not explicitly confirmed within a specified timeout period, providing a safety mechanism that prevents administrators from being locked out due to configuration errors. This feature is particularly valuable when making changes to remote devices or modifying network connectivity settings that could break remote access.

The typical workflow involves entering commit confirmed with an optional timeout value in minutes, making necessary configuration changes that take effect immediately, testing connectivity and functionality, and issuing commit within the timeout period to make changes permanent. If the commit is not received before timeout expires, the system automatically rolls back to the previous configuration.

Common usage includes commit confirmed 5 which allows five minutes for confirmation, commit confirmed 10 for ten minutes, or simply commit confirmed which uses a default timeout typically of ten minutes. The timeout value should be sufficient for testing but short enough to limit exposure if something goes wrong and the administrator cannot recover.

This safety mechanism protects against configuration mistakes that break connectivity including incorrect interface configurations, routing errors that black-hole traffic, firewall rules that block management access, and authentication changes that prevent login. Automatic rollback ensures the device remains accessible even if changes cause problems.

Option B is incorrect because commit confirmed does not bypass validation or immediately activate without checks. All Junos commit operations including commit confirmed perform syntax validation and semantic checking before applying changes. The confirmed aspect relates to automatic rollback behavior, not validation or activation processes.

Option C is incorrect because commit confirmed does not save configuration to backup storage. While Junos maintains configuration history enabling rollback, commit confirmed specifically implements automatic rollback behavior based on timeout rather than creating backups. Configuration archiving is a separate function from the confirmed commit mechanism.

Option D is incorrect because commit confirmed does not merge configurations from multiple sources. Configuration merging occurs through load merge operations or configuration groups, not through the commit process. The confirmed commit mechanism provides automatic rollback protection rather than configuration combination functionality.

Question 48: 

Which configuration mode allows you to edit the candidate configuration in Junos?

A) Configuration mode

B) Operational mode

C) Shell mode

D) Monitor mode

Answer: A

Explanation:

Configuration mode allows editing the candidate configuration in Junos, providing a protected environment where configuration changes are made and validated before being applied to the active configuration. Entering configuration mode through the configure command creates an isolated candidate configuration that can be modified without affecting running device operation until committed.

Configuration mode provides a hierarchical command structure where administrators navigate through configuration levels using commands like edit to enter hierarchies, up to move up levels, and top to return to the top level. Within configuration mode, administrators use set to add or modify configuration, delete to remove configuration, and show to display candidate configuration.

The candidate configuration concept is fundamental to Junos configuration management, separating configuration editing from activation. Changes made in configuration mode exist only in the candidate until explicitly committed. This separation allows administrators to prepare complex configurations, validate them, and activate atomically. Multiple administrators can edit separate candidate configurations simultaneously through configure private or configure exclusive.

Benefits of the candidate configuration model include ability to prepare changes without immediate impact, validation before activation preventing syntax errors, atomic activation where all changes apply together or none apply, and ability to review and rollback if needed. This model provides safer, more controlled configuration management than directly editing running configuration.

Option B is incorrect because operational mode is for monitoring device status and executing operational commands like show, ping, and traceroute, not for editing configuration. Operational mode is the default mode after login. Administrators must explicitly enter configuration mode to make configuration changes. Operational commands do not modify device settings.

Option C is incorrect because shell mode provides access to the underlying FreeBSD operating system and is used for system-level operations like file management or advanced troubleshooting, not configuration editing. Shell mode is accessed through the start shell command and should be used carefully as it bypasses Junos safeguards. Normal configuration is done in configuration mode.

Option D is incorrect because monitor mode is not a standard Junos mode. While monitoring commands exist in operational mode like monitor interface or monitor traffic for viewing real-time information, there is no separate monitor mode for editing configuration. Configuration changes occur in configuration mode only.

Question 49: 

What does the rollback command do in Junos configuration mode?

A) Reverts the candidate configuration to a previous committed configuration

B) Deletes all configuration changes permanently

C) Restarts the device to factory defaults

D) Archives the current configuration

Answer: A

Explanation:

The rollback command reverts the candidate configuration to a previous committed configuration, allowing administrators to undo recent changes by loading an earlier configuration version. Junos automatically maintains configuration history, storing the last 50 committed configurations by default. Each commit creates a numbered rollback file enabling easy restoration of previous configurations.

Rollback files are numbered sequentially where rollback 0 represents the currently active configuration, rollback 1 is the previous configuration before the most recent commit, rollback 2 is two commits ago, and so on up to rollback 49. Administrators can view available rollback versions using show system rollback and load specific versions using rollback followed by the number.

Common rollback scenarios include recovering from configuration mistakes by rolling back to the last known good configuration, comparing current and previous configurations using show | compare rollback commands, implementing staged rollback testing by saving configurations at known milestones, and emergency recovery when changes cause unexpected problems. Rollback provides essential recovery capability.

The rollback command in configuration mode loads the specified historical configuration into the candidate configuration but does not activate it until committed. This allows administrators to review the rollback configuration before applying it, make additional changes if needed, or abandon the rollback if it is not appropriate. The workflow is rollback number, review with show, then commit to activate.

Option B is incorrect because rollback does not delete configuration changes permanently. Rollback loads a previous configuration version into the candidate, but the change must be committed to take effect. The command is reversible, and configuration history remains available. Rollback is a recovery tool, not a deletion mechanism.

Option C is incorrect because rollback does not restart the device or restore factory defaults. Device restart requires separate reboot commands, and factory default restoration uses load factory-default. Rollback simply loads previous configurations and does not affect device operational state or restore original factory configurations.

Option D is incorrect because rollback does not archive configurations. Junos automatically maintains configuration history through the commit process. Explicit archiving can be configured through archive configurations but is not the function of the rollback command. Rollback accesses existing archives rather than creating them.

Question 50: 

Which command displays real-time log messages in Junos operational mode?

A) monitor start messages

B) show log messages

C) display log real-time

D) watch log messages

Answer: A

Explanation:

The monitor start messages command displays real-time log messages in Junos operational mode, providing live streaming of system log entries as they are generated. This command is invaluable for troubleshooting active issues, observing system behavior, and watching for specific events or errors. The output updates continuously showing new messages as they occur.

Monitor commands in Junos provide real-time visibility into various system activities including monitor start messages for system logs, monitor interface for interface statistics, monitor traffic for packet capture, and monitor security for security policy matches. These commands run continuously until stopped with Ctrl+C or through monitor stop.

The monitor start messages command shows messages that match configured logging severity levels and facilities. By default, it displays messages being sent to configured log files or syslog destinations. Administrators can filter output using match conditions or adjust displayed severity levels to focus on relevant messages during troubleshooting.

Real-time monitoring is particularly useful when testing configurations and wanting to see immediate effects, troubleshooting intermittent issues that may not be captured in log files, observing protocol negotiations or state changes, and monitoring for specific error conditions. Live log viewing provides immediate feedback that static log file review cannot match.

Option B is incorrect because show log messages displays historical log entries from log files rather than real-time streaming. This command shows messages that have already been logged and stored in files. While useful for reviewing past events, it does not provide continuous updates as new messages arrive. Show commands are snapshots rather than continuous streams.

Option C is incorrect because display log real-time is not a valid Junos command. While display is used as a pipe modifier in some contexts, it is not used for real-time log viewing. The correct syntax for live log monitoring is monitor start messages. Proper command syntax is essential for effective Junos administration.

Option D is incorrect because watch log messages is not a valid Junos command. While watch exists as a Unix command for periodic command execution, Junos uses monitor for real-time displays. Watch might exist in shell mode but is not the proper operational mode command for real-time log viewing.

Question 51: 

What is the default root authentication method on a new Junos device?

A) No password is set; root login requires console access

B) Default password is “juniper”

C) Random password is generated

D) Public key authentication only

Answer: A

Explanation:

On a new Junos device, no root password is set by default, and root login requires console access without a password. This default configuration allows initial setup through console connection while preventing remote access until proper authentication is configured. The first administrative task should always be setting a strong root password to secure the device.

The root account in Junos has complete administrative privileges and access to all configuration and operational commands. Because of these elevated privileges, securing the root account is critical for device security. During initial setup, administrators should immediately configure root authentication using set system root-authentication plain-text-password command.

Security best practices for root authentication include setting strong passwords meeting complexity requirements, considering SSH key-based authentication for enhanced security, restricting root login to specific source addresses when possible, enabling audit logging for root account activities, and using role-based access control to limit need for root access. Many organizations disable direct root login entirely, requiring administrators to use personal accounts with escalation.

Once root authentication is configured, console access still requires the password unless specifically configured otherwise. Remote access via SSH, Telnet, or other management protocols also requires authentication. Leaving root authentication unconfigured creates serious security vulnerabilities as anyone with physical or remote access could gain full control of the device.

Option B is incorrect because juniper is not the default password, though it was historically used on some older Juniper devices or in documentation examples. Modern Junos devices ship without default passwords set, requiring administrators to configure authentication during initial setup. Assuming default passwords exist creates security risks.

Option C is incorrect because Junos does not generate random initial passwords. New devices have no password set for root. While some systems use random initial passwords, Junos requires explicit password configuration during setup. The lack of default password ensures administrators consciously configure authentication rather than relying on defaults.

Option D is incorrect because while public key authentication is supported and recommended, it is not the only or default authentication method on new devices. Initially, no authentication is configured at all. Public key authentication must be explicitly configured by adding SSH keys to the system configuration. Password authentication is more commonly used for initial setup.

Question 52: 

Which file contains the currently active configuration on a Junos device?

A) /config/juniper.conf.gz

B) /var/db/config/juniper.conf

C) /etc/junos.conf

D) /config/active.conf

Answer: A

Explanation:

The file /config/juniper.conf.gz contains the currently active configuration on a Junos device, stored in compressed format to save disk space. This file represents the running configuration that controls device behavior. Junos automatically manages this file, updating it during commit operations and using it during boot to restore configuration.

Understanding Junos file system structure helps with advanced troubleshooting and system recovery. Besides the active configuration, Junos maintains rollback configurations in numbered files like juniper.conf.1.gz, juniper.conf.2.gz, and so on in the same directory. These rollback files enable the rollback command functionality by providing historical configuration versions.

Administrators rarely need to directly manipulate configuration files as Junos CLI provides comprehensive configuration management. However, understanding file locations is valuable for disaster recovery scenarios, advanced troubleshooting requiring file system access, or situations where CLI is unavailable. Configuration files can be backed up by copying these compressed files to external storage.

The configuration file is compressed using gzip to reduce storage requirements. Administrators can decompress and view files using standard Unix tools in shell mode, though this is typically unnecessary as CLI commands provide better configuration viewing and management. Direct file editing is not recommended as it bypasses Junos validation and can corrupt configuration.

Option B is incorrect because while /var/db/config/ is a database directory on Junos systems, juniper.conf is not stored there in uncompressed format. The authoritative configuration location is /config/juniper.conf.gz. Various database files exist under /var/db/ for different system functions, but not the primary configuration file.

Option C is incorrect because /etc/junos.conf is not a valid configuration file location on Junos devices. The /etc/ directory contains various system files but not the main device configuration. Administrators should not create or modify files in this location expecting them to affect device configuration. Configuration belongs in /config/.

Option D is incorrect because active.conf is not the actual filename used by Junos. While conceptually the file contains the active configuration, Junos uses juniper.conf.gz as the standard naming convention. Knowing correct file locations is important for file system operations and troubleshooting that may require direct file access.

Question 53: 

What happens when you enter the commit and-quit command in Junos configuration mode?

A) Commits the candidate configuration and returns to operational mode

B) Commits configuration without validation

C) Saves configuration to external storage and exits

D) Validates configuration but does not activate it

Answer: A

Explanation:

The commit and-quit command commits the candidate configuration, activating all changes, and then automatically exits configuration mode returning to operational mode. This compound command combines two common operations into one convenient command, saving time when configuration work is complete and no further changes are needed.

The workflow with commit and-quit involves entering configuration mode, making necessary changes to the candidate configuration, reviewing changes with show commands or show | compare, executing commit and-quit which validates, activates changes, and exits configuration mode, and continuing with operational commands or logging out. This streamlined process is efficient for straightforward configuration changes.

Alternative commit commands include commit which activates changes but remains in configuration mode, commit check which validates without activating, commit confirmed which activates with automatic rollback, and commit synchronize for chassis cluster synchronization. Each variant serves specific administrative needs and scenarios.

Understanding different commit options helps administrators work efficiently while maintaining safety. Commit and-quit is appropriate when configuration work is finished, but regular commit is better when multiple related changes will be made in sequence. Commit check is valuable for validating complex changes before activation. Choosing appropriate commit commands improves configuration workflow.

Option B is incorrect because all commit variants including commit and-quit perform full validation before activation. Junos architecture separates editing from activation, with validation always occurring during commit. There is no commit option that bypasses validation, as this would risk activating invalid configurations that could break device functionality.

Option C is incorrect because commit and-quit does not save configuration to external storage. It activates the candidate configuration and exits to operational mode. Configuration backup to external storage requires explicit commands like save or file copy operations. Commit operations affect the active device configuration but do not automatically create external backups.

Option D is incorrect because commit and-quit validates and activates configuration rather than only validating. The command that validates without activation is commit check. Commit and-quit fully applies changes making them active on the device. Validation is part of the commit process, but activation also occurs.

Question 54: 

Which command shows the differences between the candidate configuration and the active configuration?

A) show | compare

B) show configuration diff

C) compare candidate active

D) diff configuration

Answer: A

Explanation:

The show | compare command displays differences between the candidate configuration being edited and the currently active configuration, showing what will change when the configuration is committed. This comparison is essential before committing changes to verify intended modifications and catch unintended changes. The output uses plus signs for additions, minus signs for deletions, and shows the context of changes.

The compare output format shows configuration statements being added with leading plus signs, statements being removed with leading minus signs, and surrounding context to locate changes within the configuration hierarchy. This diff-style format makes it easy to review exactly what will change upon commit. Large configurations benefit significantly from comparing rather than reviewing entire configurations.

Additional compare variations include show | compare rollback which compares candidate with a rollback configuration version, show configuration | compare which compares active with a rollback version, and comparing with explicit rollback numbers like show | compare rollback 1. These comparisons help understand configuration evolution over time and plan rollback operations.

Best practices for configuration changes include always reviewing differences with show | compare before committing, verifying changes match intended modifications, checking that no unintended changes appear in the diff, and using compare output for change documentation. This verification step prevents configuration errors and provides audit trail of what changed. Responsible administrators always compare before committing.

Option B is incorrect because show configuration diff is not valid Junos syntax. While configuration and diff are Junos concepts, they are not combined in this way. The pipe operator with compare is the correct syntax for displaying configuration differences. Proper command syntax is critical for effective Junos administration.

Option C is incorrect because compare candidate active is not valid Junos command syntax. Junos does not have a standalone compare command in this format. Configuration comparison uses show commands with the pipe operator and compare keyword. Understanding proper Junos syntax is fundamental to effective device management.

Option D is incorrect because diff configuration is not a valid Junos command. While diff is a Unix command for comparing files, Junos CLI uses show | compare for configuration comparison. The Junos CLI provides purpose-built commands for configuration management rather than relying on generic Unix tools in normal operational and configuration modes.

Question 55: 

What is the purpose of configuration groups in Junos?

A) To apply common configuration settings to multiple hierarchy levels

B) To restrict access to certain configuration sections

C) To compress configuration files

D) To synchronize configuration across devices

Answer: A

Explanation:

Configuration groups in Junos allow applying common configuration settings to multiple hierarchy levels, promoting configuration reuse and reducing redundancy. Groups define configuration templates that can be applied throughout the configuration hierarchy using the apply-groups statement, automatically inheriting group settings where applied. This feature significantly simplifies management of repetitive configuration elements.

Configuration groups are defined under the groups hierarchy at the top configuration level, containing normal configuration statements that mirror the main configuration structure. Once defined, groups can be applied at any configuration level using apply-groups group-name. Settings from the group are inherited and merged with local configuration, with local settings taking precedence over inherited group settings.

Common use cases for configuration groups include defining standard interface configurations for consistency across multiple interfaces, setting common protocol parameters applied to multiple instances, establishing organizational standards applied globally, and simplifying configuration templates for rapid device deployment. Groups make configurations more maintainable and less error-prone through centralized definitions.

Configuration group inheritance can be viewed using show configuration | display inheritance which expands inherited values inline showing where they originate. This visibility helps administrators understand effective configuration when groups are used. Groups can also be nested with one group applying another group, creating hierarchical configuration templates.

Option B is incorrect because configuration groups do not restrict access or provide security controls. Access restrictions are implemented through login classes and permissions, not configuration groups. Groups are purely a configuration management feature for organizing and reusing configuration elements, not a security or access control mechanism.

Option C is incorrect because configuration groups do not compress configuration files. While groups may reduce configuration size by eliminating redundancy, this is a side effect of consolidating repeated settings rather than compression. File compression in Junos uses gzip for storage files like juniper.conf.gz, which is unrelated to configuration group functionality.

Option D is incorrect because configuration groups do not synchronize configurations across devices. Configuration synchronization requires explicit mechanisms like commit synchronize for chassis clusters, NETCONF/JUNOScript for multi-device management, or automation tools. Configuration groups are local device features for organizing configuration, not multi-device synchronization mechanisms.

Question 56: 

Which operational mode command displays active routing protocol neighbors?

A) show protocols neighbors

B) show bgp summary

C) show route protocol

D) display protocol adjacency

Answer: B

Explanation:

The show bgp summary command displays active BGP routing protocol neighbors along with summary information about each neighbor including neighbor address, AS number, connection state, received and sent prefix counts, and uptime. While this command is specific to BGP, similar commands exist for other protocols like show ospf neighbor for OSPF and show isis adjacency for IS-IS.

Protocol-specific neighbor commands provide essential information for verifying protocol operation and troubleshooting connectivity issues. These commands show whether neighbor relationships are established, how long they have been active, whether routes are being exchanged, and any issues preventing successful neighbor establishment. Checking neighbors is typically the first troubleshooting step for routing problems.

For BGP specifically, show bgp summary provides overview information for all configured neighbors, while show bgp neighbor provides detailed information about specific neighbors including configuration, statistics, and state information. Additional BGP commands include show route receive-protocol bgp for routes received from specific neighbors and show route advertising-protocol bgp for routes advertised to neighbors.

Understanding protocol-specific show commands is essential for network troubleshooting. Each routing protocol has unique commands reflecting its characteristics and operation. Administrators should be familiar with neighbor display commands for protocols deployed in their networks. These commands provide critical visibility into routing protocol operation and inter-router communication.

Option A is incorrect because show protocols neighbors is not a valid Junos command. While conceptually it would be useful to have a single command showing all protocol neighbors, Junos requires protocol-specific commands. Each routing protocol has its own show commands reflecting unique protocol characteristics and information.

Option C is incorrect because show route protocol displays routes learned through specific protocols rather than neighbor relationships. This command shows routing table entries, not protocol adjacencies or neighbors. While related to protocols, route display is different from neighbor status. Both types of information are important but accessed through different commands.

Option D is incorrect because display protocol adjacency is not valid Junos syntax. While adjacency is a valid term for protocol neighbors particularly in link-state protocols, the correct commands use show rather than display. Display is used as a pipe modifier, not a primary command. Understanding correct Junos syntax is fundamental.

Question 57: 

What does the commit check command do in Junos configuration mode?

A) Validates the candidate configuration without activating it

B) Checks network connectivity after committing

C) Verifies backup storage availability

D) Monitors commit process duration

Answer: A

Explanation:

The commit check command validates the candidate configuration without activating it, performing all syntax and semantic checks that would occur during normal commit but stopping short of actually applying changes to the active configuration. This command allows administrators to verify configuration correctness before activation, catching errors early without affecting device operation.

Validation during commit check includes syntax checking for correct command structure and keywords, semantic validation ensuring configuration makes logical sense, reference checking verifying referenced objects exist, and constraint validation ensuring settings comply with platform capabilities. Comprehensive validation catches most configuration errors before they affect device operation.

Using commit check is particularly valuable when preparing complex configurations, testing configurations before maintenance windows, verifying configurations created through automation or templates, and learning Junos configuration without risk of breaking device operation. The command provides safety net allowing exploration and validation without activation risk.

The workflow using commit check involves making configuration changes in configuration mode, running commit check to validate without activating, reviewing any error messages and correcting issues, repeating until commit check succeeds without errors, then running actual commit to activate validated configuration. This methodical approach improves configuration quality and reduces errors.

Option B is incorrect because commit check does not verify network connectivity. The command validates configuration syntax and semantics but does not test actual network operation. Connectivity testing requires operational commands like ping or traceroute after configuration is activated. Commit check operates purely on configuration data without affecting device operation.

Option C is incorrect because commit check does not verify backup storage availability or interact with backup systems. The command focuses solely on configuration validation. Backup operations are separate administrative functions. Commit check validates configuration correctness without considering storage, archiving, or backup infrastructure.

Option D is incorrect because commit check does not monitor commit process duration or performance. While commit check does execute and may take time for large configurations, its purpose is validation not monitoring. Duration monitoring would require separate tools or command timing utilities. Commit check is about correctness verification not performance measurement.

Question 58: 

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

A) show version

B) show system version

C) display software version

D) get system software

Answer: A

Explanation:

The show version command displays the Junos software version running on a device along with other system information including hostname, model number, and boot time. This command provides essential information for troubleshooting, verifying software compliance, planning upgrades, and confirming device capabilities. Administrators frequently use show version to document device configurations and verify software consistency across networks.

The show version output includes multiple important fields such as the specific Junos version like 20.4R1.12, the device model and hardware platform, the hostname configured on the device, how long the device has been running since last reboot, and the kernel and routing engine status. This comprehensive information provides snapshot of device identity and operational state.

Junos version numbers follow a specific format where the first part indicates release type such as major release or service release, the second part indicates release number, and additional suffixes indicate build numbers or release versions. Understanding version numbering helps administrators evaluate feature availability, bug fix status, and compatibility with other systems.

Knowing current software version is fundamental for many operational tasks including verifying all network devices run consistent software versions, checking if specific bugs are fixed in the running version, determining if desired features are available, planning upgrade paths to newer versions, and opening support cases which require version information. Show version should be among first commands executed on unfamiliar devices.

Option B is incorrect because show system version is not valid Junos command syntax. While show system commands exist for displaying various system information, version display uses simply show version. The system keyword is not included in the version command. Correct syntax is important for efficient device management.

Option C is incorrect because display software version is not valid Junos syntax. Display is used as a pipe modifier with other commands but is not a standalone command. The correct command uses show rather than display. Understanding the distinction between show commands and display modifiers is important for proper Junos CLI usage.

Option D is incorrect because get system software is not valid Junos command syntax. While get is used in some contexts, it is not used for displaying version information. Junos uses show commands in operational mode for displaying information. Get is not a standard operational mode command for system information display.

Question 59: 

What is the purpose of the rescue configuration feature in Junos?

A) To save a known good configuration that can be quickly restored

B) To automatically fix configuration errors

C) To encrypt sensitive configuration data

D) To schedule automatic configuration backups

Answer: A

Explanation:

The rescue configuration feature in Junos allows saving a known good configuration that can be quickly restored in emergency situations, providing a safety net for configuration recovery. Administrators typically save rescue configurations after successful major changes or during stable operation periods. The rescue configuration can be restored with a single command, enabling rapid recovery from configuration problems.

Creating a rescue configuration uses the request system configuration rescue save command in operational mode, capturing the current active configuration as the rescue version. This operation should be performed when the device is operating correctly with validated configuration. Only one rescue configuration is maintained at a time, with each save operation replacing the previous rescue configuration.

Restoring rescue configuration uses rollback rescue in configuration mode, loading the saved rescue configuration into the candidate. Like other rollback operations, the rescue configuration must be committed to take effect. This two-step process allows reviewing the rescue configuration before activation and making adjustments if needed.

Common rescue configuration scenarios include recovering from failed upgrades that cause configuration issues, restoring functionality after configuration changes went wrong, quickly reverting to known good state during emergencies, and providing standardized recovery point for support operations. Rescue configuration is simpler than identifying which rollback version to use and provides clearly identified recovery point.

Option B is incorrect because rescue configuration does not automatically fix errors or perform any automatic corrections. It is simply a saved configuration that can be manually restored. Junos does not attempt to automatically repair configuration errors. Error correction requires administrator intervention through configuration changes or restoration of previous configurations.

Option C is incorrect because rescue configuration does not provide encryption for sensitive configuration data. Configuration encryption is handled through separate mechanisms for protecting sensitive data like passwords. Rescue configuration is a recovery feature, not a security or encryption feature. Sensitive data protection uses configuration encryption commands.

Option D is incorrect because rescue configuration does not provide automatic scheduled backups. Configuration archiving can be configured separately through archive commands for scheduled automatic backups. Rescue configuration is manually created at administrator discretion and serves as emergency recovery point rather than routine backup mechanism.

Question 60: 

Which configuration statement is used to set the device hostname in Junos?

A) set system host-name

B) set hostname

C) set system name

D) set device-name

Answer: A

Explanation:

The set system host-name configuration statement sets the device hostname in Junos, defining the name that appears in CLI prompts, system logs, and network communications. Hostname configuration is typically among the first configuration steps during device setup, providing human-readable identification. Descriptive hostnames following naming conventions improve network management and troubleshooting.

The complete command syntax is set system host-name hostname where hostname is the desired device name following standard hostname conventions. Hostnames should be descriptive, indicating location, role, or other identifying information. Many organizations follow standardized naming conventions ensuring consistency across their networks. Hostnames appear in CLI prompts helping administrators confirm they are working on intended devices.

Hostname configuration is mandatory for production devices as it affects CLI prompts, system logging, SNMP identification, and various network protocols. Default hostnames like Amnesiac or generic names should never be used in production. Well-chosen hostnames improve operational efficiency by making device identification immediate and unambiguous.

Related system configuration includes system domain-name for DNS configuration, system time-zone for time settings, and system name-server for DNS resolution. These basic system settings establish device identity and operational parameters. Initial device configuration typically includes these fundamental system settings before configuring interfaces and protocols.

Option B is incorrect because set hostname is not valid Junos configuration syntax. While conceptually correct, Junos requires the system hierarchy level. Configuration statements follow hierarchical structure with hostname under the system hierarchy. Understanding Junos hierarchical configuration structure is fundamental to effective configuration management.

Option C is incorrect because set system name is not the correct command. While name might seem logical, Junos specifically uses host-name for this configuration. Precise syntax is required as Junos validates configuration keywords. Using incorrect keywords results in configuration errors. Memorizing correct syntax for common configurations improves efficiency.

Option D is incorrect because set device-name is not valid Junos configuration syntax. Junos does not use device-name for hostname configuration. The device-name term does not exist in standard Junos configuration hierarchy. Understanding actual Junos configuration keywords and hierarchies is essential for successful device configuration.