[Sep-2026] F5 F5CAB4 Actual Questions and Braindumps
Pass F5CAB4 Exam with Updated F5CAB4 Exam Dumps PDF 2026
NEW QUESTION # 33
A BIG-IP Administrator defines a device Self IP. The Self IP is NOT reachable from the network. What should the administrator verify first?
- A. Verify if auto last hop is disabled.
- B. The correct VLAN has been selected.
- C. The correct Interface has been selected.
- D. The correct Trunk has been selected.
Answer: B
Explanation:
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.
NEW QUESTION # 34
A BIG-IP Administrator needs to restore a UCS file to an F5 device using the Configuration Utility.
Which section of the Configuration Utility should the BIG-IP Administrator access to perform this task?
- A. System > Configuration
- B. Local Traffic > Policies
- C. System > Archives
- D. Local Traffic > Virtual Servers
Answer: C
Explanation:
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.
NEW QUESTION # 35
A BIG-IP Administrator reviews the Plane CPU Usage performance chart and discovers a high percentage of Control Plane utilization. Which type of traffic does this indicate a higher usage of?
- A. Accelerated
- B. Tunnel
- C. Application
- D. Administrative
Answer: D
Explanation:
Comprehensive and Detailed Explanation From BIG-IP Administration Control Plane Administration documents: 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.
NEW QUESTION # 36
A BIG-IP administrator is troubleshooting inconsistent configuration objects on devices in a device group. The administrator uses the command:
tmsh run /cm watch-devicegroup-device and observes the following output:
devices <devgroup> device clu_id cl_orig cl_time last_sync
20:21 sync_test bigip_a 3273 bigip_a 14:27:00
20:21 sync_test bigip_b 1745 bigip_b 13:52:34 13:42:04
20:21 sync_test bigip_c 1745 bigip_a 13:52:34 13:42:04
What two conclusions can be made about this output? (Choose two answers)
- A. The correct configuration exists on bigip_b and bigip_c because their cluster times match.
- B. bigip_a has the latest configuration.
- C. The correct configuration exists on bigip_a and bigip_c because their cluster times match.
- D. Two of the devices in the device group have a configuration that is out of date.
- E. The config from bigip_c was synced to the other devices in the device group during the most recent ConfigSync.
Answer: B,D
Explanation:
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.
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.
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.
NEW QUESTION # 37
The BIG-IP Administrator has to investigate an issue with an HTTP virtual server. Which log file should be checked first?
- A. /var/log/audit
- B. /var/log/httpd/httpd_errors
- C. /var/log/ltm
- D. /var/log/messages
Answer: C
Explanation:
For an issue involving an HTTP virtual server, the first log file to check is /var/log/ltm . A BIG-IP virtual server is an LTM traffic-management object, and runtime events related to virtual servers, pools, pool members, monitors, availability changes, and traffic-management behavior are normally written to the LTM log. /var/log/httpd/httpd_errors is not the correct first choice because it relates to the BIG-IP Configuration Utility web service, not to an HTTP application virtual server processing client traffic. /var/log/audit records administrative configuration changes, such as who modified an object and when. /var/log/messages contains broader system-level messages but is not the primary LTM troubleshooting log. Therefore, when the problem statement specifically says an HTTP virtual server is having an issue, the control-plane troubleshooting path starts with /var/log/ltm .
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NEW QUESTION # 38
New Syslog servers have been deployed in an organization. The BIG-IP Administrator must reconfigure the BIG-IP system to send log messages to these servers. In which location in the Configuration Utility can the BIG-IP Administrator make the needed configuration changes to accomplish this? (Choose one answer)
- A. System > Configuration > Local Traffic
- B. System > Logs > Audit
- C. System > Configuration > Device
- D. System > Logs > Configuration
Answer: D
Explanation:
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
NEW QUESTION # 39
A node is a member of various pools and hosts different web applications. If a web application is unavailable, the BIG-IP appliance needs to mark the pool member down for that application pool.
What should a BIG-IP Administrator deploy at the pool level to accomplish this?
- A. A UDP monitor with a custom interval/timeout
- B. An HTTP monitor with custom send/receive strings
- C. A combination of ICMP + TCP monitor
- D. A TCP monitor with a custom interval/timeout
Answer: B
Explanation:
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.
NEW QUESTION # 40
A BIG-IP Administrator needs to check the memory utilization on a BIG-IP system. Which two methods can the BIG-IP Administrator use? (Choose two.)
- A. Run the tmsh show /sys traffic command
- B. Go to Statistics > Module Statistics > Memory in the configuration utility
- C. Go to Statistics > Module Statistics > Traffic Summary in the configuration utility
- D. Run the tmsh show /sys memory command
Answer: B,D
Explanation:
Comprehensive and Detailed Explanation From BIG-IP Administration Control Plane Administration documents: Reporting device status includes monitoring physical resource exhaustion, such as memory48. 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.
NEW QUESTION # 41
An organization is performing a major release upgrade to its BIG-IP system. The system is under medium load and has enough disk space to perform the upgrade.
Which pre-upgrade task is disruptive to regular system performance and should be performed during a maintenance window? (Choose one answer)
- A. tmsh save sys config
- B. Generate a UCS
- C. Create a QKView
- D. Reactivate the license
Answer: D
Explanation:
Comprehensive and Detailed Explanation From BIG-IP Administration Control Plane Administration documents:
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.
NEW QUESTION # 42
A user needs to generate a QKView to upload to iHealth to determine any issues with upgrading TMOS.
Where can the user generate the QKView in the Configuration Utility?
- A. System > Archives
- B. System > Configuration
- C. System > Support
- D. System > Software Management
Answer: C
Explanation:
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.
NEW QUESTION # 43
When looking at this BIG-IP prompt: root@virtual-bigip1] Peer Time Out of Sync What does the message indicate? (Choose one answer)
- A. That the peer BIG-IP is unreachable for the device group
- B. That one of the NTP sources has a skewed clock
- C. That the local time is correct, but the remote time is incorrect
- D. That there was a time synchronization issue between the BIG-IP device and its peer
Answer: D
Explanation:
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)
NEW QUESTION # 44
Which file should the BIG-IP Administrator check to determine when a Virtual Server changed its status?
- A. /var/log/audit
- B. /var/log/monitors
- C. /var/log/ltm
- D. /var/log/lastlog
Answer: C
Explanation:
Comprehensive and Detailed Explanation From BIG-IP Administration Control Plane Administration documents: 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.
NEW QUESTION # 45
A BIG-IP Administrator uses a device group to share the workload and needs to perform service on a BIG-IP device currently active for a traffic group. The administrator needs to enable the traffic group to run on another BIG-IP device in the device group.
What should the administrator do to meet the requirement? (Choose one answer)
- A. Select Traffic Group and then select Failover
- B. Select Traffic Group on Primary Unit and then select Demote
- C. Create a new Traffic Group and then fail to Standby Unit
- D. Select Traffic Group and then select Force to Standby
Answer: A
Explanation:
Traffic Groups are the mechanism BIG-IP uses to control which device owns specific application traffic in a high-availability (HA) configuration. When maintenance is required on a device that is currently active for a traffic group, the correct and recommended action is to fail over that traffic group to another device in the device group.
* Failing over the traffic group moves ownership of that traffic group (and the virtual servers associated with it) to another available device without forcing the entire device into standby.
* This allows targeted maintenance while minimizing impact to other traffic groups that may still be active on the device.
Why the other options are incorrect:
* A is unnecessary and incorrect; traffic groups are not recreated for routine maintenance.
* C forces the entire device to standby, which may move more traffic than intended.
* D (Demote) affects device trust/priority behavior and is not the standard or recommended method for moving traffic group ownership.
Therefore, selecting the Traffic Group and choosing Failover is the correct solution.
NEW QUESTION # 46
A BIG-IP Administrator defines a device Self IP. The Self IP is NOT reachable from the network.
What should the administrator verify first?
- A. Verify if auto last hop is disabled.
- B. The correct VLAN has been selected.
- C. The correct Interface has been selected.
- D. The correct Trunk has been selected.
Answer: B
Explanation:
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.
NEW QUESTION # 47
A BIG-IP Administrator needs to find which modules have been licensed for use on the BIG-IP system. In which section of the Configuration Utility can the BIG-IP Administrator find this information?
- A. System > Services
- B. System > Platform
- C. System > Support
- D. System > Resource Provisioning
Answer: D
Explanation:
Comprehensive and Detailed Explanation From BIG-IP Administration Control Plane Administration documents: Identifying the current device status includes knowing which software modules (such as LTM, ASM, or APM) are active and how much hardware resource (CPU/Memory) is allocated to them40404040. The System > Resource Provisioning screen displays the licensing status and allows the administrator to set the provisioning level (Nominal, Dedicated, or Minimum) for each module.
NEW QUESTION # 48
A BIG-IP Administrator is unable to connect to the management interface via HTTPS. What is a possible reason for this issue?
- A. The port lockdown setting is configured to Allow None.
- B. The IP address of the device used to access the management interface is NOT included in the "P Allow" list in the Configuration Utility.
- C. The IP address of the device used to access the management interface is NOT included in the
"httpd Allow" list in the CLI. - D. An incorrect management route is specified.
Answer: C
Explanation:
Management connectivity is protected by an allowed access list for the httpd daemon. Unlike TMM data ports which use 'Port Lockdown' settings, the management port's access is controlled by a specific 'Allow' list. If an administrator's IP is not explicitly included in this list, the Control Plane will reject HTTPS connection attempts to the management utility.
NEW QUESTION # 49
One of the two members of a device group has been decommissioned. The BIG-IP Administrator tries to delete the device group, but is unsuccessful. Prior to removing the device group, which action should be performed? (Choose one answer)
- A. Remove the decommissioned device from the device group
- B. Make sure all members of the device group are in sync
- C. Disable the device group
- D. Remove all members from the device group
Answer: A
Explanation:
A BIG-IP device group cannot be deleted if it still contains device members, even if one of those devices has already been decommissioned or is unreachable. Before deleting the device group, the administrator must explicitly remove the decommissioned device from the device group configuration.
Once the removed or unreachable device is deleted from the device group membership, the BIG- IP system allows the remaining administrator to successfully delete the device group.
NEW QUESTION # 50
Utility, where can the BIG-IP Administrator check system metrics such as CPU and memory usage?
- A. Statistics > Dashboard
- B. Device Management > Overview
- C. Network > Interfaces
- D. Local Traffic > Virtual Servers
Answer: A
Explanation:
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.
NEW QUESTION # 51
A BIG-IP Administrator needs to determine who changed a Virtual Server configuration.
In which log file would the BIG-IP Administrator find this data? (Choose one answer)
- A. /var/log/ltm
- B. /var/log/audit
- C. /var/log/secure
Answer: B
Explanation:
The audit log (/var/log/audit) records configuration changes made on the BIG-IP system, including:
* Who made the change (user account)
* What was changed (for example, a virtual server modification)
* When the change occurred
* How it was performed (GUI, TMSH, or API)
Why the other options are incorrect:
* /var/log/secure logs authentication events such as login successes and failures, not configuration changes.
* /var/log/ltm logs traffic-management and runtime LTM events, not administrative configuration modifications.
Therefore, the correct log file for tracking who changed a virtual server is /var/log/audit.
NEW QUESTION # 52
A BIG-IP Administrator needs to export system configuration for migration purposes. Which file type should be used?
- A. ISO
- B. SCF
- C. QKView
- D. UCS
Answer: D
Explanation:
In F5 TMOS, a User Configuration Set (UCS) is the standard archive format used for backing up and migrating a complete system configuration .
Composition: A UCS file contains all necessary configuration data, including system-specific files, license information, SSL certificates, private keys, and local user accounts.
Procedural Use: When migrating to new hardware or performing an RMA replacement, the UCS file is the primary tool used to restore the entire Control Plane state to the new device.
Restoration: It can be managed through the Configuration Utility under System > Archives or via the CLI using the tmsh load /sys ucs command
NEW QUESTION # 53
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