F5 BIG-IP Administration Control Plane Administration (F5CAB4) exam F5CAB4 Exam Dumps: Updated Questions & Answers (February 2026)

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.

watch-devicegroup-device shows (among other columns) the commit ID (cid.id / shown here as clu_id), the originating device for that commit (cid-orig / shown here as cl_orig), and the time the configuration change was made (cid.time / shown here as cl_time). The highest/newest commit ID and its time represent the most recent configuration change seen among the devices. (clouddocs.f5.com)

bigip_a has the latest configuration (A) because it shows commit ID 3273 at 14:27:00, which is newer than commit ID 1745 at 13:52:34 on bigip_b and bigip_c. (clouddocs.f5.com)

Two devices are out of date (B) because bigip_b and bigip_c are still on the older commit ID 1745, so they do not match the latest commit shown on bigip_a. (clouddocs.f5.com)

Why the other options are not supported by this output:

C is not supported: bigip_c is not showing a newer commit than the others; it’s on the older commit (1745), so it’s not the source of the most recent change. The output’s cid-orig column is what tells you where the change was made. (clouddocs.f5.com)

D/E are incorrect logic: matching cid.time between two devices only indicates they share the same change timestamp/commit, not that it is the correct or latest configuration. The “latest” is indicated by the newest commit ID/time (here, bigip_a). (clouddocs.f5.com)

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 Administration Control Plane Adminis44tration documents: In a45n Active/Standby HA pair, application traffic only flows through the Active device. If an administrator makes a change on the Standby device (which has no traffic), they must synchronize the configuration to the Active device to test it. The procedural step is to log into the Active device and "pull" the configuration from the Standby device (or push from Standby) so the Active device can process traffic using the new iRule

A QKView is a comprehensive snapshot of the device's Control Plane state, configuration, and logs used for troubleshooting. By default, the qkview utility stores its generated output file in the /var/tmp/ directory. Administrators must know this path to retrieve the file for upload to F5 iHealth or Support.

When restoring a UCS file to replacement hardware (RMA device), the license from the original device is not valid on the new system. If the UCS restore attempts to load the old license, BIG-IP reports license errors such as “License is not operational”, which can prevent traffic objects (including pools and virtual servers) from loading correctly.

To avoid this issue, F5 documentation recommends restoring the UCS without the license, using the following command:

tmsh load /sys ucs no-license

This approach:

Restores all configuration objects (LTM, networking, certificates, keys, etc.)

Excludes the invalid license tied to the old hardware

Allows the administrator to activate a new license separately on the replacement device

Why the other options are incorrect:

A. Remove the license information from the UCS archiveNot supported or recommended; UCS files should not be manually modified.

B. Revoke the license prior to restoringLicense revocation does not prevent the UCS from attempting to load license data.

D. Reactivate the license on the new device using the manual activation methodThis must be done after restoring the UCS and does not prevent the restore failure itself.

Therefore, the correct and supported method to avoid this error is C.

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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.

Monitoring and reporting current device status involves tracking the health of traffic objects like Virtual Servers20. 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 file21212121. While the audit log tracks who changed a configuration, the LTM log tracks system-initiated status changes22222222.

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.

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.