F5CAB1 Exam Dumps - F5-CA Questions and Answers

When upgrading to a newer TMOS software version, BIG-IP validates whether the current license is permitted to run that version.

This is controlled by the Service Check Date in the device’s license file.

If the Service Check Date is older than the minimum required for the target version:

The system boots into the new volume ,

But fails to load the configuration ,

And will instead present messages indicating that the configuration cannot be applied due to an invalid or outdated license .

This is a well-known behavior:

An outdated license, not reactivated before upgrade, causes configuration load failure after reboot into the new software.

Why the other options are incorrect:

A. Performed on the standby unit

Upgrading a standby unit does not cause configuration load failure.

Standby-only upgrades are standard best practice.

C. Two reboots required

BIG-IP does not require two reboots during an upgrade.

One reboot into the new volume is sufficient.

D. DNS connectivity failure

DNS connectivity does not affect configuration loading.

DNS is only needed for automatic license activation, not for applying config at boot.

Thus, the configuration failed to load because the license was not reactivated before the upgrade , making Option B correct.

BIG-IP controls access to the web-based Configuration Utility (TMUI) through the /sys httpd allow list. This parameter specifies which client IPs or subnets may initiate HTTP/HTTPS connections to the management interface.

To restrict TMUI access to only the 10.0.0.0/24 subnet:

The correct method is to modify the HTTPD allow list so that it contains only this subnet.

This requires replacing the entire current list with the new subnet using:

modify /sys httpd allow replace-all-with {10.0.0.0/24}

This ensures that only clients within 10.0.0.0/24 can reach the Configuration Utility.

Why the other options are incorrect:

Options A and C create network ACL objects under /net acl, which apply to data-plane traffic, not management-plane TMUI access. TMUI access is not controlled by LTM ACLs but by the HTTPD allow directive.

Option B is incorrect syntax and references /ltm httpd, which is not the proper object; the correct hierarchy is /sys httpd.

Thus, only modifying the /sys httpd allow list achieves the required restriction.

When performing a TMOS upgrade, F5 recommends validating the target software version to ensure that the release does not contain defects that may impact system behavior. The upgrade preparation process includes checking for known issues, validating compatibility, and reviewing advisory information for the intended version. Two primary F5 tools serve this purpose:

B. F5 iHealth

iHealth is a cloud-based diagnostic and analysis platform used to evaluate the operational state of a BIG-IP system.

Administrators upload a QKView file to iHealth to receive an automated assessment of the system. As part of upgrade planning, iHealth provides:

Version-specific issue analysis , comparing the system’s configuration and hardware against F5’s internal catalog of published issues.

Upgrade advisories , identifying potential risks such as deprecated features, module compatibility concerns, or changes in behavior between TMOS versions.

Checks against known defects , allowing administrators to determine whether the target TMOS version contains issues relevant to their deployment.

This aligns with F5’s recommended upgrade workflow, where iHealth is used before upgrading to confirm system readiness and detect software-level concerns.

D. F5 Bug Tracker

The Bug Tracker is F5’s dedicated interface for reviewing software defects across TMOS releases.

It enables administrators to:

Search for known bugs by TMOS version , module, severity, or defect ID.

Review the status of defects (open, resolved, fixed in later releases).

Identify whether high-impact or security-related issues are associated with the target upgrade version.

F5 documentation emphasizes reviewing known defects prior to installation of new software images, making the Bug Tracker a critical resource for upgrade validation.

Why the other options are not correct

A. F5 End User Diagnostics (EUD)

EUD is used exclusively for hardware diagnostics (ports, memory, fans). It does not provide software-related issue verification and is not used for upgrade planning.

C. F5 University

This is a training platform , not an operational tool. It does not provide defect listings or upgrade-specific warnings.

E. F5 Downloads

Although it provides access to software images and release notes, it is not a tool for identifying known bugs . Release notes summarize general fixes and features, but systematic bug verification requires iHealth or the Bug Tracker.

When a TMOS image (.iso file) is uploaded into the /shared/images/ directory, the BIG-IP performs an internal validation step before the ISO appears in the GUI.

1. The system verifies the internal checksum

BIG-IP automatically reads the embedded checksum inside the ISO file

Verifies integrity of the uploaded image

Confirms the file is not corrupted or incomplete

Ensures the image is a valid F5 TMOS software image

Only after this checksum verification succeeds does the image appear under:

System → Software Management → Image List

Why the other options are incorrect:

A. The system performs a reboot into a new partition

Uploading an ISO file never triggers a reboot.

C. The system copies the image to /var/local/images/

All valid TMOS images remain in /shared/images/ .

No copying occurs.

Provisioning determines:

Which BIG-IP modules are enabled (LTM, ASM, APM, AFM, DNS, etc.)

Their provisioning levels (None, Minimal, Nominal, Dedicated)

Two accurate ways to view provisioning settings are:

A. GUI — System → Resource Provisioning → Module Allocation

This is the primary GUI screen showing:

All modules

Their provisioning level

System resource distribution impact

Administrators commonly use this page to confirm or change module provisioning.

D. TMSH — list /sys provision

This tmsh command displays each module and its provisioning level:

sys provision ltm { level nominal }

sys provision asm { level none }

This is the authoritative CLI method for checking module provisioning configurations.

Why the other options are incorrect:

B. show /sys provision

Shows runtime information but not the actual configuration levels .

list is the correct command for configuration details.

C. Statistics → Module Statistics

Shows performance statistics, NOT provisioning status.

Therefore, the correct responses are A and D .

When a TMOS ISO file is transferred to /shared/images/ , the BIG-IP automatically performs a validation step:

Checksum Verification

Before the image becomes visible in the GUI, the system verifies the internal checksum embedded inside the ISO.

This ensures:

The file was fully transferred

The image is not corrupted

It matches the official F5 release signature

Only after passing this verification does the GUI display the ISO under “Available Images.”

Why the other options are incorrect:

A. Reboot into a new partition

No reboot occurs simply from uploading an image.

C. Copying into /var/local/images/

This directory is not used for ISO storage.

All valid images remain in /shared/images/ .

Thus, the correct system action is checksum verification .

License reactivation updates the BIG-IP device’s license file to ensure:

The Service Check Date is current

The device is eligible to install the intended TMOS version

Any module entitlement updates are received

Reactivation does not interrupt traffic and does not require a reboot, making it safe to perform before the maintenance window.

F5 best practices state:

Perform all non-impact tasks prior to the scheduled maintenance window

Leave the window available for activities that require rebooting, such as the software installation itself

Since license reactivation is non-disruptive , it should be done before the upgrade window starts.

Self-IPs implement a security feature known as Port Lockdown , which limits which services are reachable on a Self-IP.

However, certain services required for BIG-IP device-to-device communication bypass Port Lockdown to ensure cluster and HA functionality.

TCP 4353

TCP port 4353 is used by Device Service Clustering (DSC) for:

Device trust establishment

Configuration synchronization

Failover communication

Because BIG-IP devices must always be able to communicate for HA functions to remain operational, port 4353 is exempt from Port Lockdown rules .

Why the other options are incorrect

A. TCP 443

Not required for device trust or synchronization.

HTTPS access is fully controlled by Port Lockdown.

C. UDP 53

DNS traffic is not required for synchronization and has no exemption under Port Lockdown.

The HTTPD allow list controls which IP addresses or subnets may access the Configuration Utility (TMUI) on the BIG-IP system. The Administrator already has two subnets allowed and needs to add a single host IP to the existing list.

The object /sys httpd allow supports actions such as add , delete , and replace-all-with .

Because the goal is to add one more entry without removing the existing permitted subnets, the correct command is:

modify /sys httpd allow add { 172.28.32.22 }

This appends the new host to the existing list while preserving the previously configured networks.

Why the other options are incorrect:

Option A (replace-all-with) would overwrite the entire allow list, removing existing permitted subnets—unacceptable.

Option B (delete) would remove the existing networks and not add the required host.

Therefore, the correct administrative action is to add the jump host’s IP.

The exhibit shows the configuration of a Self IP with:

Port Lockdown: Allow Custom

A Custom List that includes the following TCP ports:

443

22

Meaning of these ports:

TCP 443 → HTTPS (TMUI — web-based management)

TCP 22 → SSH (command-line remote access)

No other TCP, UDP, or protocol entries are listed; therefore, only these two services are allowed to reach the BIG-IP via this Self IP.

Evaluating the answer choices:

Option

Service

Port

Allowed?

FTP

TCP 21

Not listed

Not allowed

SSH

TCP 22

Listed

Allowed

Telnet

TCP 23

Not listed

Not allowed

Thus, SSH is the only traffic permitted through this Self IP configuration.