Free Practice Questions for F5 F5CAB4 Exam

The correct command is tmsh show /cm sync-status because the displayed output is operational synchronization status, not configuration data. In TMSH, show is used to display runtime or current operational state, while list is used to display saved configuration objects and configured properties. The output contains status fields such as Color , Status , Summary , and Details , showing that the BIG-IP device is In Sync and that both the sync-fail-test device group and device trust group have all devices consistent. This is live ConfigSync/device-group state information under the configuration management module /cm . Therefore, the command that generates this status output is tmsh show /cm sync-status . Option A is incorrect because tmsh list /cm sync-status would attempt to list configuration, not display the operational sync status shown in the exhibit.

=========

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.

Monitoring and reporting current device status involves tracking the health of traffic objects like Virtual Servers 20 . The Control Plane logs transition events—such as a Virtual Server moving from ' Available ' (green) to ' Offline ' (red) due to health monitor failures—in the /var/log/ltm file 21212121 . While the audit log tracks who changed a configuration, the LTM log tracks system-initiated status changes 22222222 .

Management access security is a primary Control Plane configuration task3.

Management Interface Security: The BIG-IP system provides a dedicated management port that is separate from the TMM (Traffic Management Microkernel) data interfaces 4444 .

System Platform Settings: Under the System > Platform section of the Configuration Utility, an administrator can define specific IP addresses or subnets that are permitted to access the device via SSH or HTTPS (the GUI).

Port Lockdown Difference: While " Port Lockdown " settings under Network > Self IPs control access to the device through self-IP addresses on data VLANs, they do not manage the security of the dedicated management port .

Access Control Lists: For robust security, F5 recommends using the " IP Allow " or " httpd Allow " lists found in the platform settings to prevent malicious brute-force attempts or unauthorized access from non-management networks .

Time synchronization is a critical component of Control Plane management, as it ensures that logs are accurately timestamped and that High Availability (HA) trust relationships remain valid 1 .

Configuration Location : The list of configured NTP (Network Time Protocol) servers and their status is managed under System > Configuration > Device > NTP .

Procedural Importance : If the system clock drifts significantly between two devices in an HA pair, the Control Plane may experience a " Time Delta " error 33 . This drift often causes a failure in device trust, preventing the ConfigSync process from functioning correctly.

System Integrity : Accurate time is also essential for the validity of SSL/TLS certificates used for both administrative management access and high availability communication.

Verification : Administrators can use this section of the Configuration Utility to confirm that the BIG-IP is communicating with its designated upstream time sources and that the local clock is correctly synchronized to the network environment .

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

tmsh create auth user < username > 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.

The User Configuration Set (UCS) is a flexible tool designed by the Control Plane to handle various lifecycle management scenarios, including upgrades and hardware migrations.

Version Compatibility (Option B): TMOS is designed to be backward compatible. The Control Plane can ingest a UCS file created on an older version of software and automatically upgrade the configuration objects to match the current, later version during the restore process.

Platform Portability (Option C): While a UCS archive contains platform-specific information, the BIG-IP system allows for " platform-independent " restores. This is a vital procedural concept for migrating from one hardware model to another or from physical hardware to a Virtual Edition (VE).

Management of State: When restoring to a different platform or a later version, the administrator often uses specific flags (such as no-license or platform-migrate in later versions) to ensure that only the portable configuration data is applied while preserving the new platform ' s unique identifiers.

The Control Plane is responsible for ARP (Address Resolution Protocol) management for Virtual Addresses. For a Virtual Server to be reachable, the BIG-IP must respond to ARP requests for that IP. If the " ARP " setting is disabled on the Virtual Address properties, upstream routers cannot resolve the MAC address of the BIG-IP, leading to connectivity failure even if the service itself is " Available. "

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 )