F5CAB4 Questions and Answers

On a BIG-IP system, remote syslog server configuration is managed through the logging configuration framework. In the Configuration Utility, this is accessed via:

System > Logs > Configuration

This section allows the administrator to:

Define remote syslog destinations

Configure log publishers

Control which log types (system, audit, LTM, ASM, etc.) are forwarded to external syslog servers

Why the other options are incorrect:

A. System > Configuration > Local TrafficUsed for traffic management settings, not logging.

C. System > Logs > AuditDisplays audit log settings and content but does not configure remote syslog destinations.

D. System > Configuration > DeviceUsed for device-level settings such as hostname and platform configuration, not logging.

Therefore, the correct location to reconfigure BIG-IP to send logs to new syslog servers is System > Logs > Configuration.

===========

Management of the device's identity and primary out-of-band connectivity is a central Control Plane responsibility.

Platform Settings: The System > Platform section of the Configuration Utility is used to manage global hardware and system parameters, including the hostname, management IP address, and time zone.

Management vs. Data Plane: It is critical to distinguish between the management interface and TMM data interfaces. While data plane IPs (Self IPs) are configured under Network > Self IPs, the dedicated management port settings are grouped with other platform-level configurations.

Access Control: This area is also used to manage administrative security, such as restricting SSH or HTTPS access to specific management subnets or IP addresses.

Impact of Change: Changing the management IP will immediately disconnect any active GUI or SSH sessions using the current management IP. The administrator must reconnect using the newly assigned address.

Comprehensive and Detailed Explan13ation From BIG-IP Administration Control Plane Administration documents: Monitoring the physical status of the device is critical for reporting device health. In F5 nomenclature, "1.0", "1.1", etc., represent physical hardware interfaces. To verify if a physical link is up or down as reported by the Control Plane's SNMP agent, the administrator must check the Interface List located under Network > Interfaces

In F5 TMOS, administrative roles and user permissions are partition-specific. The User Manager role allows an account to manage other user accounts, but this authority is restricted to the administrative partitions to which the User Manager has been granted access.

Partition Awareness: If User1 (the User Manager) attempts to modify User2 and fails, while the full Administrator succeeds, it indicates that User2 resides in a partition where User1 does not have management rights.

Principle of Least Privilege: This principle dictates that a user should be given only the minimum level of access necessary to perform their job functions.

Procedural Solution: Granting "Administrator" privileges (Option B) would violate least privilege by giving User1 full control over all system settings and all partitions. Moving users between partitions (Options A and C) might disrupt the organizational security structure. The correct and most secure administrative action is to modify the partition access for User1 to include the partition where User2 is located. This enables User1 to manage User2’s properties while maintaining their restricted role as a User Manager.

Comprehensive and Detailed Explanation From BIG-IP Administration20 Control Plane Administration documents: Connectivity management involves ensuring that the physical layer matches the networking environment. Interface properties, including media speed, duplex settings, and MTU, are managed at the Control Plane level under the Network menu. To resolve a mismatch with an upstream switch, the administrator must navigate to Network > Interfaces to manually override auto-negotiation settings.

Restoring system states from backups is a fundamental Control Plane administrative task2. When a User Configuration Set (UCS) archive is created with encryption, it requires the correct passphrase to be decrypted and loaded during the restoration process.

UCS Command Structure: The tmsh load /sys ucs command is the specific utility for restoring these comprehensive configuration archives.

Encrypted Restores: If the archive was encrypted during creation, the passphrase argument must be appended to the command followed by the actual password used to encrypt the file.

Comparison with Other Options:

load /sys config file is used for loading text-based configuration files (like bigip.conf), not full UCS archives6.

The no-license flag is used when you want to restore a configuration without overwriting the existing license (common during RMA replacements), but it does not provide the mechanism for entering an encryption passphrase.

Managing the state of a device often involves restoring configuration backups known as User Configuration Set (UCS) files These archives contain the full system configuration, including licenses and SSL certificates. The Control Plane provides a dedicated management area for these files under System > Archives, where administrators can upload, create, and restore configuration snapshots

On BIG-IP systems that participate in a Device Service Cluster (DSC), each device compares the remote device’s system time to its own system time. If the difference is outside the ConfigSync time threshold (commonly referenced as 3 seconds by default), BIG-IP updates the shell prompt to show “Peer Time Out of Sync”, and ConfigSync operations may fail until time is corrected (typically by fixing NTP reachability/configuration, or in some cases adjusting the threshold). (cdn.studio.f5.com)

This message is specifically about time drift between peers in the trust domain/DSC—not basic reachability (so B is not what it means), and it does not prove which side is “correct” (so C is too specific). It also doesn’t directly mean an NTP source is “skewed” (A can be a cause, but the prompt message itself indicates the peer-to-peer time mismatch condition). (cdn.studio.f5.com)

Comprehensive and Detailed Explanation From BIG-IP A34dministration Control Plane Administration documents: Authentication and authorization events are handled by the system's PAM (Pluggable Authentication Modules). For Control Plane security auditing, all login attempts—whether local or remote (LDAP/RADIUS/TACACS+)—and SSH-related security events are recorded in /var/log/secure. This is the primary log for troubleshooting administrative access issues

NTP (Network Time Protocol) is vital for management connectivity and HA state synchronization. Correct time is required for log timestamping and device trust group communication46. To manage these settings, the administrator navigates to System > Configuration, where general system-level services like NTP and DNS are defined to ensure the Control Plane remains synchronized with the network environment.

Comprehensive and Detailed Exp11lanation From BIG-IP Administration Control Plane Administration documents: Monitoring specific object health is a core function of the Control Plane. While the dashbo12ard provides a global overview, granular per13formance data—such as the CPU overhead a specific Virtual Server is placing on the Traffic Management Microkernel (TMM)—is found under the Module Statistics. Navigating to Statistics > Module Statistics > Local Traffic > Virtual Servers allows an administrator to report on the current status and resource consumption of individual traffic objects.

Maintaining an accurate and synchronized clock across all members of a device group is a fundamental requir5ement for the BIG-IP Control P6lane to establis7h and maintain device tru8st9.

Time Delta Impact: As shown in the exhibit, the "Time Delta to Local Device (sec)" is 12.

Trust Mechanism: Device trust relies on secure certificate-based communication (SSL/TLS) . If the time difference between devices is too large (typically more than a few seconds), the Control Plane cannot validate the certificates, leading to a failure in the trust relationship .

ConfigSync Failure: When device trust is broken due to time drift, the systems cannot verify the identity of the peer, which directly prevents the ConfigSync process from executing on the affected device, such as bigip3.local in this scenario.

Resolution: Administrators must ensure that all devices in a high availability pair are configured to use the same reliable NTP servers to keep their system clocks aligned.

The correct command for restoring an encrypted UCS archive via the command line is D. load /sys ucs <filepath> passphrase <password>.

To determine the current failover (HA) status of a BIG-IP system using tmsh, F5 documentation explicitly states that the administrator should use the following command:

show /cm failover-status

This command displays:

The current failover state (active, standby, or offline)

Detailed failover status information

The operational HA condition of the device within a device group

According to F5 Knowledge Base Article K08452454, the documented procedure for checking failover status is:

Log in to the TMOS Shell (tmsh)

Run show /cm failover-status

Why the other options are incorrect:

A. list /cm failover shows configuration settings, not operational HA status.

B. show /sys failover is not the documented command for checking current failover status and does not align with F5’s recommended procedure.

When troubleshooting a BIG-IP system where a partition is reported as full (100% utilization), identifying and removing large or unnecessary files is the immediate next step for restoration of system stability.

Symptoms of Full Partitions: If a file system (such as the root / or /var) becomes full, it can result in unpredictable system behavior, failure to save configurations, and the inability to log in to the Web UI.

The Root (/) Partition: This partition is intentionally kept small on F5 systems. It is highly sensitive to the storage of third-party software or diagnostic files that should ideally be stored in the /shared or /var directories.

Procedural Resolution: To resolve 100% disk usage, administrators should check for large files on the affected partition using CLI commands like du -ah or find / -xdev -type f -exec du {} \; | sort -rn | head -20.

Common Culprits: Large files typically causing these issues include old core files, tech support bundles, large diagnostic logs (packet diags), or temporary files created during administrative tasks.

Diagnostics vs. Remediation: While tests like the EUD (End User Diagnostics) or platform diagnostics are useful for hardware verification, they do not resolve file system exhaustion issues that have already reached a critical 100% state.

To re27port the current status of high availability for specific traffic, an administrator must verify the Traffic Group association28. In the Configuration Utility, Virtual Server properties include the Virtual Address settings where the 'Traffic Group' is assigned29292929. If the Virtual Address is assigned to a floating traffic group (like traffic-group-1), it is configured to fail over to the standby member30303030.