Get Aug-2026 updated F5CAB4 Certification Exam Sample Questions
F5CAB4 Study Guide Cover to Cover as Literally
F5 F5CAB4 Exam Syllabus Topics:
| Topic | Details |
|---|---|
| Topic 1 |
|
| Topic 2 |
|
| Topic 3 |
|
| Topic 4 |
|
| Topic 5 |
|
| Topic 6 |
|
| Topic 7 |
|
| Topic 8 |
|
| Topic 9 |
|
NEW QUESTION # 17
A BIG-IP Administrator is setting up a new BIG-IP device. The network administrator reports that the interface has an incompatible media speed. The BIG-IP Administrator needs to change this setting manually. From which location should the BIG-IP Administrator perform this task?
- A. In the TMOS Shell Command line
- B. On the Front Console
- C. In the Configuration Utility, System > Configuration
- D. In the Configuration Utility, Network > Interface
Answer: D
Explanation:
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.
NEW QUESTION # 18
A BIG-IP Administrator needs to update the list of configured NTP servers. In which area of the Configuration Utility should the BIG-IP Administrator perform this update?
- A. System > Services
- B. System > Platform
- C. System > Preferences
- D. System > Configuration
Answer: D
Explanation:
Comprehensive and Detailed Explanation From BIG-IP Administration Control Plane Administration documents: 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.
NEW QUESTION # 19
Administrative user accounts have been defined on the remote LDAP server and are unable to log in to the BIG-IP device. Which log file should the BIG-IP Administrator check to find the related messages?28
- A. /var/log/secure
- B. /var/log/user.log
- C. /var/log/ltm
- D. /var/log/messages
Answer: A
Explanation:
Comprehensive and Detailed Explanation From BIG-IP A34dministration Control Plane Administration documents: Authentication and authorization events are handled by the system's PAM (Pluggable Authentication Modules). For Control Plane security auditing, all login attempts-whether local or remote (LDAP/RADIUS/TACACS+)-and SSH-related security events are recorded in /var/log/secure. This is the primary log for troubleshooting administrative access issues
NEW QUESTION # 20
An LTM device has a virtual server mapped to www.f5.com. Users report that when they connect to /resources/201.1.2h.l_l.com they are unable to receive content. What is the likely cause of the issue?
- A. The pool associated with the virtual server is falling its health check.
- B. The pool associated with the virtual server does not have priority group activation enabled.
- C. The virtual address does not have ARP enabled.
- D. The virtual address does not have route advertising enabled.
Answer: C
Explanation:
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."
NEW QUESTION # 21
Which method is recommended for creating a new user from the CLI? (Choose one answer)
- A. Run useradd 'username' then passwd username from bash or tmsh
- B. Run f5adduser 'username' then f5passwd username from bash or tmsh
- C. Run tmsh create auth user username prompt-for-password from bash
- D. Edit bigip.conf to add the new user and the user's clear-text password
Answer: C
Explanation:
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.
NEW QUESTION # 22
Which command will provide the BIG-IP Administrator with the current device HA status? (Choose one answer)
- A. show /sys failover
- B. list /cm failover
- C. show /cm failover-status
Answer: C
Explanation:
Comprehensive and Detailed Explanation From BIG-IP Administration Control Plane Administration documents:
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.
NEW QUESTION # 23
Administrative user accounts have been defined on the remote LDAP server and are unable to log in to the BIG-IP device.
Which log file should the BIG-IP Administrator check to find the related messages? (Choose one answer)
- A. /var/log/secure
- B. /var/log/user.log
- C. /var/log/ltm
- D. /var/log/messages
Answer: A
Explanation:
When BIG-IP is configured to use remote authentication (such as LDAP), all authentication and authorization attempts-including successes and failures-are logged to /var/log/secure.
For LDAP-based administrative login issues, /var/log/secure contains:
* LDAP authentication failures
* PAM authentication errors
* Authorization and access-denied messages
* Details explaining why a remote user could not log in
Why the other options are incorrect:
* /var/log/user.log is not a standard BIG-IP log file for authentication.
* /var/log/ltm logs traffic management events, not user authentication.
* /var/log/messages contains general system messages but not detailed authentication failure information.
Therefore, the correct log file to troubleshoot LDAP administrative login failures is /var/log/secure.
NEW QUESTION # 24
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. The correct Trunk has been selected.
- B. The correct Interface has been selected.
- C. Verify if auto last hop is disabled.
- D. The correct VLAN has been selected.
Answer: D
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 # 25
The BIG-IP Administrator suspects unauthorized SSH login attempts on the BIG-IP system.
Which log file would contain details of these attempts? (Choose one answer)
- A. /var/log/secure
- B. /var/log/ltm
- C. /var/log/audit
- D. /var/log/messages
Answer: A
Explanation:
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.
NEW QUESTION # 26
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 config from bigip_c was synced to the other devices in the device group during the most recent ConfigSync.
- B. The correct configuration exists on bigip_b and bigip_c because their cluster times match.
- C. Two of the devices in the device group have a configuration that is out of date.
- D. The correct configuration exists on bigip_a and bigip_c because their cluster times match.
- E. bigip_a has the latest configuration.
Answer: C,E
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. (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)
NEW QUESTION # 27
A BIG-IP Administrator needs to change the management IP address of a BIG-IP device. Where should the administrator perform this task?
- A. System > Platform
- B. Network > VLANs
- C. Network > Self IPs
- D. Network > Interfaces
Answer: A
Explanation:
Management of the device's identity and primary out-of-band connectivity is a central Control Plane responsibility.
* Platform Settings: The System > Platform section of the Configuration Utility is used to manage global hardware and system parameters, including the hostname, management IP address, and time zone.
* Management vs. Data Plane: It is critical to distinguish between the management interface and TMM data interfaces. While data plane IPs (Self IPs) are configured under Network > Self IPs, the dedicated management port settings are grouped with other platform-level configurations.
* Access Control: This area is also used to manage administrative security, such as restricting SSH or HTTPS access to specific management subnets or IP addresses.
* Impact of Change: Changing the management IP will immediately disconnect any active GUI or SSH sessions using the current management IP. The administrator must reconnect using the newly assigned address.
NEW QUESTION # 28
A BIG-IP Administrator makes a configuration change to a Virtual Server on the Standby device of an HA pair. The HA pair is currently configured with Auto-Sync Enabled. What effect will the change have on the HA pair configuration?
- A. The change will take effect when Auto-Sync propagates the config to the HA pair.
- B. The change will be propagated next time a configuration change is made on the Active device.
- C. The change will be undone next time a configuration change is made on the Active device.
- D. The change will be undone when Auto-Sync propagates the config to the HA pair.
Answer: A
Explanation:
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
NEW QUESTION # 29
Refer to the exhibit.
The BIG-IP Administrator is investigating disk utilization on the BIG-IP device. What should the BIG-IP Administrator check next? (Choose one answer)
- A. Results from the platform diagnostics test
- B. Large files on the / file system
- C. Results from the EUD test
- D. Large files on /usr file system
Answer: B
Explanation:
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.
NEW QUESTION # 30
Which role has full administrative access in BIG-IP?
- A. Guest
- B. Administrator
- C. Operator
- D. Resource Administrator
Answer: B
Explanation:
The Administrator role has complete access to all system features.
NEW QUESTION # 31
A BIG-IP Administrator needs to view the CPU utilization of a particular Virtual Server. Which section of the Configuration Utility should the administrator use for this purpose?
- A. Statistics > Module Statistics > Local Traffic > Virtual Servers567
- B. Statistics > Analytics > Process CPU Utilization234
- C. Statistics > Module Statistics > Local Traffic > Virtual Addresses
- D. Statistics > Module Statistics > Traffic Summary1
Answer: A
Explanation:
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.
NEW QUESTION # 32
A BIG-IP Administrator needs to export system configuration for migration purposes. Which file type should be used?
- A. QKView
- B. SCF
- C. UCS
- D. ISO
Answer: C
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 The correct location to restrict management access to specific subnets is D. System > Platform1.
NEW QUESTION # 33
What is the purpose of administrative partitions?
- A. Isolate configuration objects
- B. Improve CPU performance
- C. Route packets
- D. Encrypt traffic
Answer: A
Explanation:
Partitions separate administrative domains within a BIG-IP system.
NEW QUESTION # 34
Where is the BIG-IP running configuration primarily stored?
- A. /usr/local/bin
- B. /etc/passwd
- C. /config/bigip.conf
- D. /var/log/messages
Answer: C
Explanation:
This file contains the active configuration managed by MCP.
NEW QUESTION # 35
The BIG-IP system is provisioned for LTM only. The BIG-IP Administrator is tasked with provisioning ASM.
What process restarts when the BIG-IP Administrator changes the module provisioning? (Choose one answer)
- A. tmm
- B. bd
- C. sshd
- D. httpd
Answer: A
Explanation:
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.
NEW QUESTION # 36
Refer to the exhibit.
The BIG-IP Administrator runs the command shown and observes a device trust issue between BIG-IP devices in a device group. The issue prevents config sync on device bigip3.local. What is preventing the config sync?
- A. Both devices are standby
- B. Next Active Load factor is 0 on bigip1.local
- C. Next Active Load factor is 1 on bigip1.local
- D. Time Delta to local system is
Answer: D
Explanation:
Maintaining an accurate and synchronized clock across all members of a device group is a fundamental requir5ement for the BIG-IP Control P6lane to establis7h and maintain device tru8st9.
* Time Delta Impact: As shown in the exhibit, the "Time Delta to Local Device (sec)" is 12.
* Trust Mechanism: Device trust relies on secure certificate-based communication (SSL/TLS) . If the time difference between devices is too large (typically more than a few seconds), the Control Plane cannot validate the certificates, leading to a failure in the trust relationship .
* ConfigSync Failure: When device trust is broken due to time drift, the systems cannot verify the identity of the peer, which directly prevents the ConfigSync process from executing on the affected device, such as bigip3.local in this scenario.
* Resolution: Administrators must ensure that all devices in a high availability pair are configured to use the same reliable NTP servers to keep their system clocks aligned.
The correct command for restoring an encrypted UCS archive via the command line is D. load /sys ucs < filepath> passphrase <password>.
NEW QUESTION # 37
Administrative user accounts have been defined on the remote LDAP server and are unable to log in to the BIG-IP device.
Which log file should the BIG-IP Administrator check to find the related messages? (Choose one answer)
- A. /var/log/secure
- B. /var/log/user.log
- C. /var/log/ltm
- D. /var/log/messages
Answer: A
Explanation:
Comprehensive and Detailed Explanation From BIG-IP Administration Control Plane Administration documents:
When BIG-IP is configured to use remote authentication (such as LDAP), all authentication and authorization attempts-including successes and failures-are logged to /var/log/secure.
For LDAP-based administrative login issues, /var/log/secure contains:
LDAP authentication failures
PAM authentication errors
Authorization and access-denied messages
Details explaining why a remote user could not log in
Why the other options are incorrect:
/var/log/user.log is not a standard BIG-IP log file for authentication.
/var/log/ltm logs traffic management events, not user authentication.
/var/log/messages contains general system messages but not detailed authentication failure information.
Therefore, the correct log file to troubleshoot LDAP administrative login failures is /var/log/secure.
NEW QUESTION # 38
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 > Archives
- B. System > Configuration
- C. Local Traffic > Policies
- D. Local Traffic > Virtual Servers
Answer: A
Explanation:
Comprehensive and Detailed Explanation From BIG-IP Administration Control Plane Administration documents: 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 # 39
......
100% Real & Accurate F5CAB4 Questions and Answers with Free and Fast Updates: https://www.prepawaytest.com/F5/F5CAB4-practice-exam-dumps.html
Get Unlimited Access to F5CAB4 Certification Exam Cert Guide: https://drive.google.com/open?id=18cWP5AmcxqksyC2g8GswDK17X_sNQL-Y