F5 F5CAB2 Exam Dumps - Actual Questions Answers

For BIG-IP to send or receive traffic on a VLAN, that VLAN must be bound to a physical interface or a trunk . Creating a VLAN object and a Self IP alone is not sufficient to establish data-plane connectivity.

From the exhibit:

The VLAN ( vlan_1033 ) exists and has a tag defined.

A Self IP is configured and associated with the VLAN.

However, traffic cannot reach servers on that VLAN.

This indicates a Layer 2 connectivity issue , not a Layer 3 or HA issue.

Why assigning a physical interface fixes the problem:

BIG-IP VLANs do not carry traffic unless they are explicitly attached to:

A physical interface (e.g., 1.1), or

A trunk

Without an interface assignment, the VLAN is effectively isolated and cannot transmit or receive frames, making servers unreachable regardless of correct IP addressing.

Why the other options are incorrect:

A. Set Port Lockdown to Allow All Port Lockdown controls which services can be accessed on the Self IP (management-plane access), not whether BIG-IP can reach servers on that VLAN.

B. Change Auto Last Hop to enabled Auto Last Hop affects return traffic routing for asymmetric paths. It does not fix missing Layer 2 connectivity.

D. Create a Floating Self IP address Floating Self IPs are used for HA failover. They do not resolve reachability issues on a single device when the VLAN itself is not connected to an interface.

Conclusion:

The servers are unreachable because the VLAN has no physical interface assigned . To restore connectivity, the BIG-IP Administrator must assign a physical interface (or trunk) to the VLAN , enabling Layer 2 traffic flow.

When handling high-volume UDP traffic where the BIG-IP does not need to maintain any session history or relationship between packets, a Stateless virtual server is the appropriate choice.

No Connection Tracking: A stateless virtual server does not create or maintain entries in the BIG-IP connection table. This means the system processes each packet as an individual event, without " considering previous connections " or packets from the same source.

High Performance: Because the system bypasses the overhead of state management, stateless virtual servers provide the highest possible throughput for UDP and ICMP traffic.

Use Cases: This is ideal for services like DNS (stateless queries) or some types of syslog traffic where each packet is independent and doesn ' t require the persistence or protocol inspection typically provided by a full-proxy.

Why other options are incorrect:

Forwarding: While a Forwarding (IP) virtual server can handle UDP, it still maintains a state entry in the connection table to ensure return traffic is handled correctly.

Standard: This is a full-proxy virtual server. It is inherently stateful and requires a connection table entry for every flow it manages.

Reject: This is a special virtual server type that simply drops incoming traffic and, in the case of TCP, sends a reset (RST) or, for UDP, sends an ICMP unreachable message. It is not a load balancing type.

This scenario combines session continuity , multiple protocols (HTTP and FTP) , and HA failover behavior , which directly implicates persistence handling across devices and services .

Key Requirements Breakdown

Same pool member for entire session

Session must survive failover

Session must span multiple services (HTTP and FTP)

Why Persistence Mirroring + Match Across Services Is Required

Persistence Mirroring

Ensures persistence records are synchronized from the active BIG-IP to the standby BIG-IP.

Without mirroring:

After failover, the standby device has no persistence table

Clients are load-balanced again

Sessions break, forcing users to restart

Persistence mirroring is essential for session continuity during failover

Match Across Services

Allows a single persistence record to be shared across multiple virtual servers / protocols

Required when:

HTTP and FTP must use the same pool member

Multiple services are part of a single application session

Together, these settings ensure:

Persistence survives device failover

Persistence is honored across HTTP and FTP

Why the Other Options Are Incorrect

A. Cookie persistence and session timeout Cookie persistence only applies to HTTP and does not address FTP or failover synchronization.

B. Stateful failover and Network Failover detection Stateful failover applies to connection state , not persistence records , and does not link HTTP and FTP sessions.

D. SYN-cookie insertion threshold and connection low-water mark These are DoS / SYN flood protection settings, unrelated to persistence or HA behavior.