Practice Free F5CAB4 BIG-IP Administration Control Plane Administration (F5CAB4) exam Exam Questions Answers With Explanation

Audit logging is a specialized feature within TMOS designed to track administrative actions. According to F5 documentation, whenever a system object (like a virtual server, pool, or profile) is created, modified, or deleted, the system records the event. These logs are stored specifically in /var/log/audit. This is essential for control plane administration to track "who did what and when" regarding the device configuration.

The Statistics Dashboard is the primary graphical interface used by administrators to monitor the real-time performance and health of the BIG-IP system.

System-Wide Overview: Navigating to Statistics > Dashboard provides a centralized view of critical system-level metrics, including global CPU utilization (across all TMM instances and the Linux host) and total memory usage.

Performance Tracking: In addition to CPU and memory, the dashboard displays other vital statistics such as total active connections, throughput (bits/packets per second), SSL transactions per second (TPS), and compression efficiency.

Operational Health: Monitoring these metrics from the dashboard allows the administrator to quickly identify performance trends or resource exhaustion that could impact the Control Plane or Data Plane stability.

Comparison to Other Menus:

Local Traffic > Virtual Servers: Provides statistics specific to traffic objects rather than global system resources.

Network > Interfaces: Shows physical layer statistics like link status, errors, and drops for specific ports.

Device Management > Overview: Focuses on high availability (HA) states, synchronization status, and device trust rather than granular performance metrics.

The recommended and supported method for creating BIG-IP users from the CLI is through TMSH, using the authentication subsystem.

tmsh create auth user prompt-for-password:

Properly creates the user within BIG-IP’s AAA/authentication framework

Encrypts the password securely

Ensures the user is stored and managed correctly in the BIG-IP configuration database

Is fully supported and documented

Why the other options are incorrect:

B is unsafe and unsupported because editing bigip.conf directly and storing clear-text passwords violates security and configuration management best practices.

C (f5adduser / f5passwd) is deprecated and not recommended for modern BIG-IP versions.

D creates a Linux system user only, not a BIG-IP administrative user, and will not allow access to the Configuration Utility or TMSH roles.

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

Reactivating a BIG-IP license is a traffic-disruptive operation. During the license reactivation process, the BIG-IP system performs a configuration reload, which results in a temporary interruption of all traffic processing. Because traffic handling is affected, F5 explicitly recommends scheduling license updates during a maintenance window.

This behavior is documented in F5 Knowledge Base articles, which state that license reactivation impacts traffic and must be planned accordingly during upgrades or system changes.

The other options are not considered disruptive:

Creating a QKView is primarily a diagnostic task and does not interrupt traffic.

Running tmsh save sys config only saves the running configuration to disk.

Generating a UCS is resource-intensive but does not reload configuration or interrupt traffic processing.

When a BIG-IP Administrator changes module provisioning (for example, enabling ASM on a system previously provisioned only for LTM), the BIG-IP system must restart the Traffic Management Microkernel (TMM) process.

The TMM process is responsible for:

Traffic handling

LTM, ASM, and other traffic-processing modules

Enforcing security and application policies

Provisioning changes affect how traffic modules are loaded and integrated into TMM. As a result, TMM is restarted, which causes a temporary interruption of traffic processing. This is expected behavior and is why module provisioning changes should be planned during a maintenance window.

Why the other options are incorrect:

A. bd is related to blade/platform management, not module provisioning.

C. sshd handles SSH access and is not affected by provisioning changes.

D. httpd supports the Configuration Utility (GUI) and does not restart due to module provisioning.

Therefore, the correct answer is B. tmm.

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The EUD is a 33hardware-level diagnostic tool that runs outside of the TMOS operating system. Because it is used when the system cannot boot or is in a pre-boot state, it cannot be accessed via the GUI or management network. The administrator must connect physically via the serial Console Port to interact with the boot menu and initiate the hardware tests.

Comprehensive and Detailed Explanation From BIG-IP Administratio24n Control Plane Administration documents: TMOS Device Service Cluste25ring (DSC) allows for configuration changes to be made on any device within a synchronization group. If Auto-Sync is enabled, the Control Plane detects the change on the Standby unit and automatically propagates (pushes) that updated configuration to the other members of the HA pair

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.

Connectivity management requires a proper logical-to-physical mapping within the BIG-IP Control Plane.

VLAN Association: In TMOS, a Self IP address is not assigned directly to a physical interface. Instead, it is assigned to a VLAN (Virtual Local Area Network) object.

Procedural Troubleshooting: If a Self IP is unreachable, the primary failure point is often that the IP was associated with the wrong VLAN, or the VLAN itself is not correctly associated with the intended physical interface or trunk.

Layer 2 Mapping: The Control Plane requires the VLAN to be "up" and "untagged" or "tagged" on a valid interface for traffic to flow. If the administrator selects the incorrect VLAN, the Self IP will exist in the configuration but will be logically isolated from the physical network wire.

On BIG-IP systems, all authentication attempts for administrative access—including logins to the Configuration Utility (GUI)—are logged in /var/log/secure. This log file records:

Successful and failed login attempts

The username used

The authentication method (local, LDAP, RADIUS, etc.)

Access denials and PAM authentication errors

Why the other options are incorrect:

/var/log/pam/tallylog tracks account lockouts and failed attempt counters, not detailed login attempts.

/var/log/ltm logs traffic management events, not administrative authentication.

/var/log/httpd logs web server activity but does not record authentication success or failure for BIG-IP administrative users.

Therefore, the correct log file to verify whether a user attempted to log in to the BIG-IP Configuration Utility is /var/log/secure.

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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 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.

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

Generating a QKView is a standard procedure for identifying device health and upgrade readiness42. Within the Configuration Utility, this Control Plane diagnostic tool is located under System > Support43. This utility collects configuration and state data into a single file used by the iHealth 'Upgrade Advisor' to report on known bugs or compatibility issues prior to a version change.