Free F5-Networks F5CAB1 Exam Dumps Questions

Which one of the following is a port and protocol combination allowed by the Allow Default setting for Port Lockdown?

Correct Answer:C
Port Lockdown controls which ports and protocols aSelf IPwill respond to.
TheAllow Defaultsetting permits only a predefined set of BIG-IP internal and required service ports.
The Allow Default listincludes:
TCP 443# HTTPS (Management/TMUI access via Self-IP)
TCP 4353 # CMI (device sync)
TCP/UDP ports related to HA communication
Other essential internal F5 ports
Why TCP 443 is correct:
It is one of the officially allowed ports underAllow Default.
It enables HTTPS/TMUI access through a Self IP.
Why the other options are incorrect:
* A. TCP 80 (HTTP)
Not allowed under Allow Default
HTTP via Self-IP is blocked unless placed under Allow Custom
* B. UDP 8443
Not an F5 default service
Not part of the Allow Default ports

What will setting a Self IP to??Allow None??for Port Lockdown do?

Correct Answer:A
ThePort Lockdownfeature controls which services a Self-IP will respond to.
Setting a Self-IP toAllow Nonemeans:
The Self-IP will not acceptanytraffic except the very limited, hard-coded HA ports such asTCP 4353
used for device trust and configuration sync.
All other HA ports, including those needed for network failover and other HA mechanisms,are blocked.
When essential HA services cannot communicate, each device assumes its peer is down. This results in:
HA failover misbehavior
Both devices thinking the other is offline
Potentialactive-active condition, which is not intended and can cause traffic disruption
Thus,Allow Nonecan break HA functionality unless the Self-IP is not used for HA links.

A BIG-IP Administrator is responsible for deploying a new software image on an F5 BIG-IP HA pair and has scheduled a one-hour maintenance window.
With a focus on minimizing service disruption, which of the following strategies is the most appropriate?

Correct Answer:C
For BIG-IP high-availability (HA) pairs, F5's recommended upgrade workflow prioritizesservice continuity,predictable failover, andminimal downtime. The established best-practice sequence is:
Upgrade the standby unit first
Because the standby device is not passing traffic, upgrading and rebooting it does not impact production.
Boot the standby unit into the newly installed version
Once online, the administrator verifies basic health, device sync status, cluster communication, and module functionality.
Perform a controlled failover to the upgraded unit
Traffic shifts to the newly upgraded device, allowing validation of the configuration and operational behavior under real traffic loads.
Upgrade the second device (now standby)
The previously active device becomes standby after failover, allowing it to be safely upgraded and rebooted without interruption.
This phased approach ensures only one device is unavailable at a time, allowing continuous traffic flow throughout the upgrade process.
Why the Correct Answer is C
OptionCexactly matches F5's documented production-safe upgrade method:
Upgrade thestandbynode first
Reboot into new image
Failover to upgraded device
Validate
Upgrade the remaining (now-standby) device
This procedure minimizes risk and traffic disruption.
Why the other options are incorrect:
* A. Upgrade the active node first
Upgrading the active device requires removing it from service and failing over abruptly. This is not recommended and increases service disruption risk.
* B. Resetting device trust
Resetting trust is unnecessary and can disrupt configuration sync, peer communication, and cluster operation. It is not part of any standard upgrade workflow.
* D. Upgrading and rebooting both nodes simultaneously
This would causetotal outage, because both HA members would be unavailable at the same time.

A BIG-IP Administrator needs to verify the state of equipment in the data center. A BIG-IP appliance has asolid yellow indicatoron the status LED.
How should the administrator interpret this LED indicator?

Correct Answer:C
Explanation
BIG-IP hardware platforms use chassis LEDs to indicate system health states.
Asolid yellow status LEDtypically indicates awarning condition, such as:
A non-critical hardware alert
A temperature threshold nearing limit
A minor fan or sensor irregularity
Other non-fatal environmental or system conditions
This state reflects awarning-level alarm, meaning the unit is operational but requires investigation.
Why the other options are incorrect
* A. Halted or EUD mode
This is associated with different LED patterns (usually flashing conditions or specific color codes), not a solid yellow status LED.
* B. Standby in device group
HA state is not indicated by the chassis status LED.
Standby status is alogicaldevice state, not a hardware LED state.
* D. Power supply failure
Power supply indicators use separate LEDs located on each power module (usually flashing amber/red), not the system status LED.
Thus, asolid yellow status indicatorsignifies awarning-level alarm.

The BIG-IP Administrator uses Secure Copy Protocol (SCP) to upload a TMOS image to the/shared/images/ directory in preparation for an upgrade.
After the upload is complete, what will the system dobeforethe image appears in the GUI under:
System » Software Management » Image List?

Correct Answer:B
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 systemverifies the internal checksumembedded 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 isnotused for ISO storage.
All valid images remain in/shared/images/.
Thus, the correct system action ischecksum verification.

A new logging solution is being implemented on the network. Policy requires keeping management traffic sent from the BIG-IPout of the management interface. After configuring the BIG-IP to forward messages to the new Syslog server, the BIG-IP Administrator notices that packets are being sentfrom a numbered data-plane Self IP.
What should the BIG-IP Administrator change to send the traffic out of thecorrect interface?

Correct Answer:B
By default,management-plane trafficuses themanagement routing table, whiledata-plane trafficuses theTMM routing table.
Remote Syslog traffic ismanagement-planetrafficunlessa management route exists.
If noManagement Routematches the Syslog server??s destination IP, the BIG-IP will instead:
UseTMM routes, and
Source the packets from aSelf IP
This is exactly what the administrator is observing.
To force Syslog traffic out the management port:
You must create aManagement Route, which is configured using:
tmsh create /sys management-routegatewaynetwork
This sends syslog traffic:
Out of themanagement interface
Using theManagement IPas the source
Thus,Option Bis correct.
Why the other options are incorrect:
* A. Set the Management IP as the source address
Source address selection is overridden by routing.
Without a management route, traffic still goes out the data plane.
* C. Create a new Self IP using a route domain
Unnecessary and not related to management-plane routing.
Syslog traffic should not rely on data-plane Self IPs.
* D. Modify port lockdown on Self IP to allow UDP/514
This would allow Syslog trafficintothe BIG-IP over a Self IP, not forceoutboundtraffic via management.