F5-CTS-LTM Practice Test 7 — 10 Questions

Question 1

An application requires persistence based on a specific custom header named 'X-Session-ID'. The LTM Specialist has confirmed the header is always present in requests. Which persistence method is most appropriate?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Universal persistence. Universal persistence is the only method that allows the BIG-IP to persist traffic based on arbitrary data found within the request. By extracting the value of the 'X-Session-ID' header using an iRule and mapping it to a persistence record, the BIG-IP can ensure that all requests with the same session ID are consistently routed to the same backend server, regardless of the client's IP address.

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Cookie Insert persistence

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Source Address persistence

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Hash persistence

Question 2

Which component of the BIG-IP LTM architecture is primarily responsible for the initial processing and decision-making regarding whether a packet should be forwarded to a pool member?

Accepted Answer

The Virtual Server. The Local Traffic Manager (LTM) module utilizes virtual servers to intercept incoming traffic. The virtual server acts as the central point of control, evaluating incoming packets against configured rules, policies, and profiles. This architecture allows the LTM to make intelligent load balancing decisions, ensuring traffic is directed to the most appropriate pool member based on system state, performance, and specific business logic requirements.

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The Pool Member

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The Health Monitor

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The iControl API

Question 3

An LTM is configured with a 'OneConnect' profile. What is the primary purpose of this feature?

Accepted Answer

To reuse backend TCP connections for multiple client requests.. OneConnect enables TCP connection pooling between the BIG-IP and the backend servers. By keeping backend connections open even after a client request finishes, the LTM avoids the overhead of repeated TCP handshakes. This is essential for high-performance web applications, as it significantly reduces latency and server CPU consumption, allowing the backend servers to handle a higher volume of concurrent user requests more efficiently than they could with per-request connection establishment.

Answer

To encrypt traffic between the BIG-IP and the backend servers.

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To enable persistence for HTTP traffic.

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To limit the number of concurrent connections per client.

Question 4

An administrator needs to ensure that a pool member remains part of the load balancing rotation only if it responds to specific HTTP GET requests on port 80, rather than just TCP SYN. Which action should the administrator perform?

Accepted Answer

Create and assign an HTTP monitor with a specific 'Send' and 'Receive' string.. To validate application-level health rather than just network reachability, a custom monitor is required. By creating an HTTP or HTTPS monitor, the BIG-IP sends specific requests and verifies the content of the response. This ensures that the web service itself is functional, not just the underlying operating system or network stack, preventing the delivery of requests to unresponsive or malfunctioning application services.

Answer

Configure an ICMP monitor on the pool member.

Answer

Enable the 'Priority Group Activation' feature on the pool.

Answer

Change the pool's Load Balancing method to 'Least Connections'.

Question 5

Which statement best describes the difference between a 'Node' and a 'Pool Member' in the BIG-IP LTM configuration?

Accepted Answer

Nodes represent the physical IP, whereas pool members represent the service port.. A Node is a device defined by its IP address, which exists independently of any pool. A Pool Member is an instance of a node assigned to a specific pool, often including port and monitor settings. This distinction is crucial because multiple pools can reference the same node, allowing administrators to manage health and load balancing for different services independently on the same physical backend server.

Answer

Nodes are defined at the virtual server level, while pool members are defined globally.

Answer

Nodes are only used for health monitoring, while pool members handle traffic.

Answer

Pool members are not required for load balancing traffic.

Question 6

What is the primary function of a BIG-IP LTM monitor?

Accepted Answer

To determine the availability of a pool member.. Monitors are used to verify the operational status and health of backend pool members. By periodically checking specific services, the BIG-IP ensures that traffic is only sent to functional servers. This prevents black-holing traffic and maintains high availability, as the BIG-IP will automatically stop sending requests to any member that fails its configured health check, providing seamless failover for users.

Answer

To encrypt traffic between the client and the BIG-IP.

Answer

To balance traffic load across multiple pool members.

Answer

To translate source IP addresses for outgoing traffic.

Question 7

Which component is responsible for executing iRules on the BIG-IP LTM system?

Accepted Answer

The Data Plane (TMM).. The Traffic Management Microkernel (TMM) is the core engine of the BIG-IP system responsible for processing all traffic. iRules are executed directly within TMM as packets are processed, allowing for line-rate traffic manipulation. This architecture ensures that complex logic, such as header modification or persistence redirection, occurs in real-time with minimal latency, which is a major advantage of the LTM's purpose-built hardware acceleration and software design.

Answer

The Control Plane (MCPD).

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The Linux Kernel.

Answer

The REST API daemon (restjavad).

Question 8

An LTM administrator needs to ensure that client SSL traffic is offloaded at the BIG-IP while maintaining end-to-end encryption to the backend servers. Which profile configuration is required to achieve this?

Accepted Answer

Assign both a Client SSL profile and a Server SSL profile to the virtual server.. To achieve SSL offloading with backend encryption, the LTM must terminate the client-side SSL using a Client SSL profile and then initiate a new SSL connection to the server using a Server SSL profile. This architecture, known as SSL Bridging, is critical for organizations needing to perform deep packet inspection or Layer 7 load balancing while maintaining security compliance protocols between the load balancer and the internal server pool members.

Answer

Apply only a Client SSL profile to the virtual server.

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Configure a FastL4 profile with SSL persistence enabled.

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Disable the Client SSL profile and enable a Server SSL profile only.

Question 9

Refer to the exhibit. The virtual server 'vs_secure_site' is showing as 'offline'. What is the most immediate step to take to restore service?

Accepted Answer

Investigate the pool members and health monitor status.. When a virtual server status is 'offline' due to 'no available members', it indicates that all pool members associated with that virtual server have failed their health checks. The most immediate and logical step is to inspect the pool members and their monitors to identify why they are failing, as the virtual server cannot function without at least one healthy backend server.

Answer

Delete and recreate the virtual server.

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Restart the BIG-IP TMM service.

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Change the virtual server IP address.

Question 10

When using an iRule to select a pool, what happens if the iRule contains a logic error that results in no pool being selected?

Accepted Answer

The system selects the default pool defined on the VS.. If an iRule does not issue a 'pool' command, the BIG-IP defaults to the pool defined on the Virtual Server itself. If no pool is defined on the VS, the connection is reset. Understanding this fallback behavior is vital for debugging complex iRule logic. If an administrator fails to account for all conditions in an iRule, the traffic may behave unpredictably, falling back to default settings rather than failing outright.

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The connection is immediately dropped.

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The system routes traffic to the first pool in the list.

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The iRule execution stops and returns an error to the client.