F5CAB1 Practice Test 6 — 10 Questions

Question 1

Which action should an administrator take to ensure that a newly installed BIG-IP system is secure before placing it into a production environment?

Accepted Answer

Change the default 'root' and 'admin' passwords.. Security is paramount in initial configuration. Changing default credentials, disabling unnecessary services, and configuring management network restrictions are fundamental steps to harden the appliance. By addressing these items immediately, administrators prevent unauthorized access and reduce the attack surface, ensuring the system aligns with corporate security policies before it starts handling any sensitive client-side traffic.

Answer

Enable all available management services.

Answer

Keep the default SSL certificate for management.

Answer

Disable logging to save disk space.

Question 2

Which step must be taken to ensure that an F5 BIG-IP device is properly licensed before it can be used for load balancing?

Accepted Answer

Activate the registration key with F5.. Licensing is a mandatory prerequisite that defines the capacity and features of the BIG-IP platform. This process verifies the entitlement of the unit through F5's activation servers. Mastering this step is essential for any administrator, as it is the very first task in any new installation, and the device will not allow any traffic-processing modules to be provisioned until the license is validated and applied.

Answer

Manually add the license to the /etc/hosts file.

Answer

Download a license from a third-party vendor.

Answer

Run a packet capture on the management interface.

Question 3

Which component of the BIG-IP initial setup is used to ensure that administrative access to the system is restricted to trusted management subnets?

Accepted Answer

Management port allowed addresses. The 'Management IP' configuration includes the ability to set packet filter rules or restrict GUI/SSH access via management allowed lists. Limiting access ensures that only specific, authorized subnets can interact with the management plane. This is a vital security best practice, preventing unauthorized actors from attempting to log in to the management interface of the F5 device from public or untrusted network segments.

Answer

Self-IP allow list

Answer

Route table configuration

Answer

VLAN tagging policies

Question 4

Refer to the exhibit. An administrator receives this error while installing a new version. What is the recommended way to resolve this space issue?

Accepted Answer

Delete old, unused software images in the boot locations.. Disk space management is a frequent operational challenge. By removing unused software images from the boot partitions, the administrator clears the necessary space to extract the new image. This process ensures the system can complete the installation without needing to reformat or wipe existing data, maintaining stability during the upgrade cycle which is essential for environments with limited storage capacity on older hardware.

Answer

Reformat the hard drive.

Answer

Increase the disk partition size via CLI.

Answer

Disable the logging service.

Question 5

When configuring a new VLAN on a BIG-IP, what happens if the VLAN is not assigned to any interfaces?

Accepted Answer

The VLAN will be created but cannot pass traffic.. A VLAN that has no assigned interfaces is effectively an internal-only construct. While it can exist in the configuration, it cannot receive or transmit traffic to the external network because there is no physical or virtual path for the packets to enter or leave the BIG-IP system. This is a common configuration state when creating internal-only segments, but it prevents the VLAN from fulfilling its role as a bridge for production traffic.

Answer

The system will generate a critical alarm.

Answer

The system will automatically assign the default management interface.

Answer

The VLAN creation will fail immediately.

Question 6

After upgrading a BIG-IP from v13.1 to v16.1, the administrator notices that several custom iRules are failing to load. What is the most appropriate first step to resolve this issue?

Accepted Answer

Check the /var/log/ltm file for specific syntax error messages.. Major upgrades often include changes to the iRules syntax or the underlying Tcl interpreter, leading to deprecated commands. Checking the /var/log/ltm file is the standard first step because it contains specific error messages identifying which line and command in the iRule failed to load. This allows the administrator to pinpoint the exact syntax issue rather than guessing, which is crucial for minimizing downtime during post-upgrade maintenance.

Answer

Delete and recreate the iRules from scratch.

Answer

Reboot the unit back to the previous version immediately.

Answer

Restore the entire configuration from a backup.

Question 7

An administrator is installing a new BIG-IP system and needs to configure the management interface. The administrator wants to ensure that the device is reachable on the network for remote administration. Which configuration step is required?

Accepted Answer

Assign an IP address, subnet mask, and default gateway to the management interface using the LCD panel or the console.. The management interface must be configured with a static IP address, subnet mask, and default gateway to enable remote administration. This is typically done during initial setup via the LCD panel or console. The management interface is separate from data plane interfaces and should be on a dedicated management network for security and reliability.

Answer

Enable DHCP on the management interface and rely on the DHCP server to assign an address.

Answer

Configure the management interface as a trunk and assign multiple VLANs to it.

Answer

Configure a self IP address on VLAN 1 and use that for management access.

Question 8

Which tool should an administrator use to monitor the status of the BIG-IP upgrade process in real-time?

Accepted Answer

The 'tmsh show sys software' command.. The 'tmsh' (Traffic Management Shell) command-line interface provides the most reliable and real-time visibility into the upgrade process. By using commands like 'show sys software', an administrator can monitor the installation percentage, status of the target volume, and identify any errors as they happen. This is superior to the GUI, which may not update as reliably during major system-level transitions like firmware installations.

Answer

The browser-based performance graphs.

Answer

The 'tcpdump' utility.

Answer

The 'f5mcpd' logs in the GUI.

Question 9

When upgrading a BIG-IP system using the Software Management utility, which TWO of the following tasks are strictly required to ensure a successful transition between major software versions?

Accepted Answer

Validate the configuration using the 'tmsh load sys config verify' command.. Upgrading BIG-IP systems requires careful preparation, specifically ensuring the configuration is compatible with the target version and that the boot location has sufficient capacity. Performing a configuration check (qkview/TMSH check) prevents common upgrade failures related to deprecated features or syntax changes. Verifying storage space ensures the installation process does not fail mid-installation, preventing corrupted boot partitions and potential system downtime during the upgrade window.

Answer

Install all hotfixes available on the F5 Downloads site before the major upgrade.

Answer

Delete all existing snapshots to free up space in the /var partition.

Answer

Reboot the unit into the current version to clear RAM cache.

Question 10

An administrator is upgrading a high-availability pair. What is the standard procedure to ensure zero-downtime during the upgrade process?

Accepted Answer

Upgrade the standby node first.. The standard procedure involves upgrading the standby unit first, ensuring it is healthy, then failing over traffic to the upgraded unit. Finally, the former active unit is upgraded. This approach ensures that one device is always ready to process traffic, maintaining high availability throughout the maintenance window. It mitigates the risk of a full outage and allows for immediate rollback if the new version displays unexpected behavior on the standby node.

Answer

Upgrade both units simultaneously.

Answer

Upgrade the active node first.

Answer

Perform a 'force offline' on both nodes.