F5 F5CAB1 - BIG-IP Administration Install, Initial Configuration, and Upgrade

Securing the BIG-IP management interface is a fundamental administrative responsibility. F5 best practices emphasize restricting who can reach the management port and ensuring that only authorized systems are allowed access.

A. Limiting management access to trusted network segments

F5 recommends placing the management interface on adedicated, isolated, and secured management network or VLAN, rather than exposing it to production or untrusted networks.

This reduces the attack surface by ensuring only trusted segments have visibility to administrative interfaces.

D. Restricting management access by IP or subnet

F5 BIG-IP uses the/sys httpd allowlist (for HTTPS) and configuration options insshd(for SSH) to control which IP addresses or subnets can access the device.

By specifying only known administrative IPs or ranges, unauthorized users cannot reach the login services.

Why the other options are incorrect

B. Blocking all management HTTPS/SSH ports

This would prevent any administrative access and is not a viable security practice.

C. Using Self-IP addresses for administrative access

F5 explicitly warns against using Self-IPs for management access unless strictly necessary.

Self-IPs are exposed to the data plane and should not be used as the primary administrative interface.

In BIG-IP, software images are installed onboot volumes(for example, HD1.1, HD1.2, HD1.3, etc.).

To install software on anew volume, the administrator must instruct the system to create a new boot location before installation.

There are two correct ways to create a new volume:

A. tmsh command (with correct syntax)

tmsh install software image /shared/images/BIGIP-.iso volume HD1.5 create-volume

This syntax correctly includes:

install software image

full path to ISO (/shared/images/...)

volume name (HD1.5)

create-volumekeyword

This instructs BIG-IP to create the new boot volume as part of the installation.

C. Using the GUI → System > Disk Management

From the Disk Management menu, the administrator can:

Select “New Volume”

Enter the volume identifier (e.g., HD1.5)

Apply changes

This GUI method is officially supported and explicitly creates a new boot volume before installing the software.

Why the other options are incorrect:

B. Incorrect tmsh syntax

Missing /shared/images/ path

Incorrect command structure

D. Incorrect command structure

Missing required keywords and correct command hierarchy

E. Software Management → Install does NOT create volumes

This installs to anexistingvolume only

The GUI install dialog does not create new boot volumes

Thus, onlyOption AandOption Cproperly create a new software volume.

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 theService Check Datein the device’s license file.

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

The systemboots into the new volume,

Butfails to load the configuration,

And will instead present messages indicating that the configuration cannot be applied due to aninvalid 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 thelicense was not reactivated before the upgrade, makingOption Bcorrect.