F5CAB4 BIG-IP Administration Control Plane Administration (F5CAB4) exam Questions and Answers

In netstat output:

0.0.0.0:443 means the service is bound to all available IPv4 interfaces on the system.

LISTEN indicates the service is actively waiting for incoming connection requests.

Therefore, this output confirms that a service (commonly HTTPS/443, such as the BIG-IP Configuration Utility or an application listener) is actively listening on all interfaces, making B the correct answer.

Why the other options are incorrect:

A would show 127.0.0.1:443 if it were loopback-only.

C is incorrect because LISTEN explicitly indicates readiness to accept connections.

D is unrelated; standby state does not affect socket binding shown by netstat.

Hence, the correct answer is B.

On BIG-IP systems, authentication and authorization events are logged in /var/log/secure. This includes:

Successful and failed SSH login attempts

Invalid user authentication attempts

PAM (Pluggable Authentication Module) authentication failures

Access denials related to secure services

Why the other options are incorrect:

/var/log/messages contains general system messages and service events, not detailed authentication failures.

/var/log/audit records administrative configuration changes (who changed what and when), not login attempts.

/var/log/ltm logs traffic-management (TMM) and application-related events.

Therefore, the correct log file for investigating unauthorized SSH login attempts is /var/log/secure.

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Reporting device status includes monitoring physical resource exhaustion, such as memory. The Control Plane provides both a command-line method via TMSH (show /sys memory) and a graphical method under Statistics > Module Statistics > Memory to report on how memory is allocated across TMM and the Linux host494949494949494949. This is essential for identifying potential "Aggressive Mode" triggers or hardware performance bottlenecks50.

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.

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.

The "Management Port" is distinct from TMM data ports. Configuration for global platform-level settings, including administrative access restrictions (IP Allow lists for SSH and HTTPS) for the management port, is found under System > Platform. This is a critical Control Plane hardening step to prevent unauthorized remote access

Here is the next batch of 10 questions from your document that are 100% related to BIG-IP

To maintain integrity in a High Availability environment, TMOS prevents the deletion of active Devic28e Groups. Procedurally, a device group is a container for synchronization; the Control Plane requires that you first strip the group of all associated members (devices) before the group object itself can be removed from the configuration.

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

When a failover occurs, the newly active device must inform the surrounding network that it now "owns" the shared IP addresses. Without MAC Masquerade, the new device uses its own hardware MAC, requiring upstream routers to update their ARP tables (which causes a delay). MAC Masquerading allows the HA pair to share a "floating" MAC address, ensuring the Control Plane transition is transparent to the network layer

Managing the license is a primary Control Plane task required to activate software modules and features on a BIG-IP device.

License Management Utility: All actions related to the device license, including initial activation, renewal, and adding add-on keys, are performed under the System > License section of the Configuration Utility.

Procedural Requirements: Licensing often requires the generation of a "dossier," which is a unique encrypted string used by the F5 License Server to generate the final license file.

Impact on Services: Updating or re-activating a license generally requires a restart of system services (such as the tmm daemon), which will temporarily disrupt traffic processing unless performed on a standby unit in a high availability pair.

Add-on Licenses: If an administrator needs to increase the capacity of a specific module (like increasing the SSL TPS limit or adding a new module like ASM), the new registration keys are entered through this same interface using the "Re-activate" button.

BIG-IP provides two supported and documented methods to manually force a device into standby state in a high-availability (HA) configuration:

CLI method (A):

tmsh run /sys failover device standby

This is the correct and supported TMSH command to force the local device to transition from active to standby.

Configuration Utility method (B):Navigating to Device Management > Devices > Local Device (Self) and selecting Force to Standby performs the same operation through the GUI and is fully supported.

Why the other options are incorrect:

C is incorrect: Traffic Groups do not provide a “Force to Standby” option for the local device; traffic groups are used to manage which device owns specific traffic, not to force device-level failover.

D is incorrect: tmsh run /sys failover standby is not a valid TMSH command. The correct syntax requires device standby.

Thus, the correct answers are A and B.

F5 architecture distinguishes between the Data Plane (TMM processing application traffic) and the Control Plane (Linux host processing management tasks). High Control Plane CPU utilization typically points to administrative activities such as heavy GUI usage, complex API calls (iControl), large-scale configuration synchronizations, or intensive logging/monitoring tasks rather than the actual switching or load balancing of application data.

BIG-IP supports remote authentication by integrating with centralized authentication services through its AAA framework. The supported and commonly used remote authentication servers include:

LDAP (A)Used to authenticate users against directory services such as Active Directory or other LDAP-compliant directories.

RADIUS (C)Commonly used for centralized authentication, authorization, and accounting, especially in network and security environments.

Why the other options are incorrect:

OAUTH (B) is an authorization framework, not supported as a direct administrative authentication backend for BIG-IP management access.

SAML (D) is primarily used for single sign-on (SSO) in application authentication scenarios, not for BIG-IP administrative login authentication.

Thus, the correct remote authentication server types are LDAP and RADIUS.

Although /var/log/ltm is primarily associated with Local Traffic Manager events, it is also the primary destination for system-level alerts generated by the Control Plane's chmand (Chassis Manager Daemon). Hardware status changes, including power supply failures, fan speeds, and temperature warnings, are logged as "notice" or "critical" events within the LTM log file.

In a BIG-IP Device Service Cluster (DSC), manual configuration synchronization is performed using the ConfigSync framework. The supported and documented command to manually push the local configuration to a specific device group is:

tmsh run cm config-sync to-group

This command:

Initiates a one-time manual ConfigSync

Pushes the local device’s configuration to all members of the specified device group

Is commonly used when auto-sync is disabled or when the administrator wants explicit control over synchronization timing

Why the other options are incorrect:

A is not a valid TMSH command for ConfigSync.

B enables auto-sync but does not perform an immediate synchronization.

D is not a valid or supported TMSH command for device group configuration synchronization.

Therefore, the correct command to manually synchronize configuration to a device group is C.

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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.

Comprehensive and Detailed Explanation From BIG-IP Administration Control Plane Admi13nistration documents:

To accurately report the current status of specific web applications hosted on the same server (node), the Control Plane must use a monitor that operates at the application layer.

Application-Specific Monitoring: While a node (the IP address) might be up and responding to ICMP (ping) or TCP handshakes, a specific web service or path on that server could be failing.

Custom Send Strings: An HTTP monitor allows the administrator to define a "Send String" to request a specific page or URI related to the application in that pool .

Receive Strings: The "Receive String" identifies a unique value that the application must return to be considered "Available" .

Granular Status Reporting: By deploying these monitors at the pool level, the Control Plane can mark a pool member "Offline" for one application pool if the receive string is missing, while keeping it "Available" in another pool where the service is still healthy.