F5 201 Exam Dumps & Practice Test Questions

Question 1:

What is a likely explanation for a pool showing a red (offline) status, assuming the monitor configurations below represent all applied monitoring assignments?

A. No monitors are configured for any pool, member, or node
B. A monitor is assigned to the pool, but none of the pool members have passed the health check
C. A monitor is assigned to the pool, and only some pool members have passed the check
D. Monitors are assigned to all nodes, and they have passed, but the pool members have no specific monitors assigned

Correct Answer: B

Explanation:

In a load balancer environment like F5 BIG-IP, understanding how health monitors impact the status of pools is critical to maintaining high availability. Monitors are used to assess the health of various components—such as nodes, pool members, or the pool itself—by executing checks at regular intervals. If these checks fail, the component is marked as offline or degraded. A red status means the pool is unavailable, and understanding why this occurs requires a clear understanding of monitor assignment and evaluation logic.

Let’s evaluate the correct answer first:

B. A monitor is assigned to the pool, but none of the pool members passed the health check
This is the correct explanation for a red (offline) pool status. When a monitor is attached directly to the pool, it is applied to each of the pool members within it. If none of the pool members pass the monitor’s health checks (for instance, if all are returning a failed HTTP response or are unreachable), the load balancer has no healthy resources to route traffic to. As a result, the entire pool is marked as offline. This is a direct and logical result of a failed health evaluation.

Now consider why the other options are incorrect:

A. No monitors are configured for any pool, member, or node
If no monitors are configured, many load balancers, including BIG-IP, may consider the pool available by default. Some systems may mark it as unknown, but not explicitly offline. Therefore, an offline status would not occur solely due to the absence of monitors.

C. A monitor is assigned to the pool, and only some members passed
In this case, since at least one member is deemed healthy, the pool is not fully down. It would typically show a partially available or degraded status (often yellow or orange), not a red/offline status.

D. Monitors are assigned to all nodes, and all have passed, but no monitors are assigned to pool members
While healthy nodes are a good sign, if pool members (which represent the node + port combination) are not monitored directly, the pool may not reflect this health correctly. But again, this condition is not sufficient to mark the pool as explicitly offline.

In conclusion, the only situation that directly results in a pool being red/offline is when a monitor is assigned to the pool and all members fail the health checks, making B the correct answer.

Question 2:

You are configuring a virtual server on a BIG-IP system to terminate SSL from clients and maintain session persistence using a cookie generated by the system. 

Which four profiles must be assigned to the virtual server? (Select four.)

A. TCP
B. HTTP
C. HTTPS
D. ClientSSL
E. ServerSSL
F. Cookie-Based Persistence

Correct Answers: A, B, D, F

Explanation:

To configure a virtual server on an F5 BIG-IP for SSL termination and cookie-based session persistence, a combination of profiles is required. Each profile serves a distinct function across layers of the OSI model—from transport to application to session management.

Here is why each correct profile is essential:

A. TCP
This is a fundamental requirement. SSL (i.e., HTTPS) traffic operates over TCP. The TCP profile enables the virtual server to manage transport-level behaviors such as connection establishment, retransmissions, and window scaling. Without it, the server cannot handle the underlying network traffic, making it indispensable.

B. HTTP
Because cookie persistence is implemented using HTTP headers, this profile must be included. It enables the BIG-IP to read, inspect, and manipulate HTTP content once SSL is decrypted. The HTTP profile is essential for inserting persistence cookies and for other application-layer traffic manipulations.

D. ClientSSL
This profile is responsible for SSL termination. It allows the BIG-IP to decrypt client-side SSL traffic by using configured certificates, keys, and ciphers. Without this, the BIG-IP cannot handle encrypted traffic, which would make it impossible to inspect or modify HTTP headers for cookie persistence.

F. Cookie-Based Persistence
Persistence ensures that a client’s session is consistently directed to the same pool member. This profile adds a custom cookie to HTTP responses, which is sent back by the client on subsequent requests. The BIG-IP uses this cookie to maintain session stickiness—a critical requirement for stateful applications.

Now, let's look at why the other profiles are incorrect:

C. HTTPS
This is not an actual BIG-IP profile. HTTPS refers to a protocol (HTTP over SSL), but BIG-IP handles this using separate profiles: ClientSSL for decryption and HTTP for application-level handling. Therefore, this option is invalid.

E. ServerSSL
This profile is used if the BIG-IP re-encrypts traffic before forwarding it to the backend servers. However, the question only mentions terminating SSL at the BIG-IP, so there’s no requirement for outbound SSL. Thus, ServerSSL is unnecessary in this scenario.

In summary, to terminate SSL and maintain session stickiness via cookies, the four necessary profiles are: TCP, HTTP, ClientSSL, and Cookie-Based Persistence—making A, B, D, and F the correct answers.

Question 3:

A network engineer is configuring a BIG-IP virtual server to decrypt incoming HTTPS traffic and then forward that traffic as plain HTTP to backend servers. 

Which two profile types must be associated with this virtual server to support such a setup? (Choose two.)

A. TCP
B. HTTP
C. HTTPS
D. ClientSSL
E. ServerSSL

Correct Answers: A, D

Explanation:

In this use case, the BIG-IP system is required to terminate incoming HTTPS traffic—decrypt it at the edge—and then forward it in unencrypted HTTP format to the internal servers. This is a typical SSL offloading scenario, where the BIG-IP handles the computational burden of encryption/decryption to reduce processing on backend systems.

To correctly configure this behavior, two types of profiles are mandatory:

• A. TCP (Correct):
  Every virtual server that handles TCP-based protocols (like HTTP or HTTPS) must have a TCP profile. This profile manages how the BIG-IP system handles connections, including aspects like buffering, timeouts, window size, and congestion control. It is the foundational transport-level profile and must be present for the virtual server to establish and manage client-side TCP connections.

• D. ClientSSL (Correct):
  This profile is specifically used for decrypting incoming SSL/TLS traffic from the client. The ClientSSL profile allows the BIG-IP to terminate the SSL session, handle certificate presentation, and interpret encrypted client requests. Since the requirement is to terminate HTTPS (SSL/TLS) at the BIG-IP, this profile is absolutely necessary. It defines which certificate to present and which ciphers to support, among other security parameters.

Now let’s review the incorrect choices:

• B. HTTP (Incorrect):
  An HTTP profile enables advanced features like content rewriting, compression, and persistence based on HTTP headers. While useful in many scenarios, it is not mandatory for simply decrypting HTTPS and forwarding traffic as HTTP. If HTTP-level inspection or manipulation is needed, then it could be included, but it is not essential for the basic SSL termination and forwarding setup.

• C. HTTPS (Incorrect):
  There is no such profile type called “HTTPS” in BIG-IP. HTTPS is simply HTTP over SSL, and it is managed using ClientSSL and ServerSSL profiles. This makes option C invalid, as it refers to a protocol, not a profile.

• E. ServerSSL (Incorrect):
  This profile is used when traffic must be re-encrypted before being sent to the backend servers. Since the question specifies that traffic should be forwarded unencrypted, using ServerSSL would contradict that requirement.

Summary:
To terminate SSL from clients and forward HTTP to servers, the virtual server must include a TCP profile for transport-layer handling and a ClientSSL profile for SSL termination. These are the only two profiles strictly required.

Question 4:

Which of the following statements accurately describe the characteristics of profiles in a BIG-IP load balancing system? (Choose three.)

A. Built-in default profiles cannot be created or removed.
B. Every custom profile must be derived from a parent profile.
C. A profile can function as both a child and a parent in the profile hierarchy.
D. Any changes to a parent profile are always applied to its child profiles.
E. It’s possible to configure a virtual server without assigning any profiles.

Correct Answers: A, B, C

Explanation:

In BIG-IP and other advanced load balancing platforms, profiles define how traffic is handled for specific protocols and operations—like TCP behavior, SSL termination, or HTTP optimizations. Understanding how these profiles are created, inherited, and used is key to building efficient and consistent configurations.

Let’s review the correct answers first:

• A. Default profiles cannot be created or deleted (Correct):
  BIG-IP includes built-in default profiles such as tcp, http, and clientssl. These serve as templates or fallbacks and cannot be deleted or recreated. They are protected system objects that offer administrators a known configuration baseline. Although you can clone these to create custom profiles, the originals remain untouched to ensure stability and recovery options.

• B. Custom profiles are always based on a parent (Correct):
  Any custom profile must inherit from an existing profile. This allows administrators to reuse common configurations and make only necessary changes, promoting consistency. Whether the parent is a system default or another custom profile, the inheritance model ensures easier management and scalability.

• C. A profile can be both a child and a parent (Correct):
  Profiles in BIG-IP support multi-level inheritance. A custom profile may derive settings from a parent and simultaneously act as a parent to other custom profiles. For example, a base clientssl_custom profile may be the foundation for other environment-specific profiles like clientssl_prod or clientssl_dev. This hierarchy allows for flexible configuration layering.

Now, the incorrect options:

• D. All changes to parent profiles are propagated to child profiles (Incorrect):
  This is only partially true. Child profiles inherit values from the parent unless they explicitly override them. If a child profile has customized a particular setting, then any change in the parent’s equivalent setting will not affect the child. Therefore, inheritance is selective, not absolute.

• E. Virtual servers can be configured without profiles (Incorrect):
  Profiles are essential for virtual server operation. Even if not explicitly assigned, BIG-IP applies default profiles to enable basic functionality. For instance, a TCP virtual server requires at least a TCP profile to handle transport-layer communication. Thus, saying profiles are optional is incorrect.

Summary:
The correct characteristics are that default profiles cannot be deleted, custom profiles always inherit from a parent, and profiles can act as both parents and children in a layered configuration. These principles ensure modularity and maintainability in BIG-IP environments.

Question 5:

Which method of implementing cookie-based persistence on a load balancer like F5 BIG-IP requires the least changes to the existing web server configuration?

A. insert
B. rewrite
C. passive
D. session

Correct Answer: A

Explanation:

In load balancing systems such as F5 BIG-IP, cookie persistence is a mechanism that ensures a user’s requests are continuously directed to the same backend server during their session. This is critical for applications that store session data on a specific server instance rather than in a centralized location.

Among the different cookie persistence strategies—insert, rewrite, passive, and session—the insert method is the least invasive and requires no changes to the web server’s configuration. This simplicity makes it particularly useful in environments where rapid deployment or minimal disruption to existing infrastructure is desired.

With the insert method, the F5 device creates a new cookie—typically called something like BIGipServer<pool-name>—and inserts it into the client’s HTTP response. The client browser returns this cookie with each subsequent request. Since the web server itself doesn’t have to generate or process this cookie, no updates to the application code or server configuration are required. The logic and tracking are entirely handled by the load balancer.

On the other hand:

• Rewrite modifies an existing cookie set by the application. This requires awareness of how the application names and manages cookies. Developers may need to modify naming conventions or structures to make this work.

• Passive uses a cookie that is already set by the application and simply reads it to determine session persistence. While less invasive than rewrite, it still assumes the application is generating cookies in a consistent and usable format. Configuration on the server or in code might be necessary.

• Session generally refers to server-managed persistence mechanisms. It often involves additional backend changes such as session databases or stickiness logic and is less efficient in distributed environments.

Ultimately, the insert method offloads persistence handling entirely to the F5 device, enabling session stickiness without any dependencies on server-side logic. This approach is especially helpful when deploying cookie persistence to legacy applications or third-party systems where server-side changes are undesirable or impractical.

Thus, for a quick and server-agnostic implementation of cookie persistence, the insert method (A) is the best and most efficient choice.

Question 6:

Which of the following statements accurately describes a key characteristic of cookie persistence?

A. Cookie persistence works independently of client IP addresses.
B. Cookie persistence is effective even with end-to-end encrypted traffic.
C. The cookie stores virtual server, pool, and member details in plain text.
D. Cookies are always saved to a user’s file system if accepted.

Correct Answer: A

Explanation:

Cookie persistence is a popular load balancing strategy where a cookie is used to maintain session affinity—ensuring that all requests from a user during a session are routed to the same backend server. This is particularly important for stateful applications that store session data locally.

The correct answer is A, which states that cookie persistence is independent of the client’s IP address. This is a fundamental advantage of this method. In many environments, especially those involving NAT (Network Address Translation), proxies, or mobile networks, the client’s IP address can change between requests. Using IP-based persistence (like source address affinity) in such cases becomes unreliable. However, cookie persistence embeds a tracking identifier within the client’s browser that remains consistent across these requests, allowing for accurate session stickiness regardless of the client’s IP address.

Let’s analyze why the other statements are incorrect:

• B. Cookie persistence is effective even with end-to-end encrypted traffic – This is not accurate. If SSL is not terminated at the load balancer, it cannot inspect or modify HTTP headers, including setting or reading cookies. For cookie persistence to work, the load balancer must terminate SSL/TLS (perform SSL offloading) so it can insert and read cookies. If traffic is encrypted from the client all the way to the backend (end-to-end encryption), cookie persistence won't work.

• C. The cookie stores virtual server, pool name, and member IP in clear text – This is partially true but misleading. While F5's default cookie (BIGipServer) contains encoded information about the backend server, it does not explicitly include the virtual server or pool name in a readable format. Additionally, this value can be encrypted or obfuscated using custom settings, so the data is not always in plain text.

• D. Cookies are always saved to a user’s file system if accepted – This is not always true. Most persistence cookies used by load balancers are session cookies, which are stored in memory and deleted when the browser is closed. Whether a cookie is saved to disk depends on whether it has an expiration date (i.e., persistent cookie) or not.

In summary, cookie persistence is powerful because it decouples session stickiness from IP addresses, making it robust in complex network environments. For this reason, option A accurately captures a key benefit of this technique.

Question 7:

When a virtual server is configured with a ServerSSL profile on an F5 BIG-IP device, what type of SSL certificates are required on the backend pool members?

A. Backend servers do not need SSL certificates at all.
B. The only requirement is that the SSL certificates exist on the pool members.
C. The SSL certificates must be signed by a trusted Certificate Authority (CA).
D. The certificates must be generated by the same company that owns the BIG-IP device.

Correct Answer: C

Explanation:

In an F5 BIG-IP environment, when a virtual server is configured with a ServerSSL profile, it means that SSL re-encryption is being used. This scenario involves decrypting SSL traffic from the client at the BIG-IP device, and then re-encrypting that traffic before forwarding it to the backend pool members. For this to work securely, the BIG-IP acts as a client to the backend servers and expects them to present valid SSL certificates during the SSL handshake.

Let’s analyze the certificate requirements in this setup:

• A. Backend servers do not need SSL certificates at all:
  This is incorrect. In order for the BIG-IP to establish a secure SSL session with the pool members, those servers must have SSL certificates installed. Without certificates, the SSL handshake would fail and traffic could not be securely transmitted to the pool members.

• B. The only requirement is that the SSL certificates exist on the pool members:
  This is misleading. While having a certificate is necessary, it is not sufficient. The BIG-IP will verify the certificate's authenticity and trust chain. If the certificate is self-signed or untrusted (unless explicitly configured to bypass validation), the SSL connection will fail or generate warnings/errors.

• C. The SSL certificates must be signed by a trusted Certificate Authority (CA):
  This is the correct answer. By default, the BIG-IP device expects to validate the server certificate, which includes checking that it is signed by a recognized and trusted CA, has a valid date, and matches the expected domain or common name. If you want to allow self-signed certs or skip certificate verification, you can change those settings in the ServerSSL profile—but that’s not the standard default behavior.

• D. The certificates must be generated by the same company that owns the BIG-IP device:
  This is overly restrictive and inaccurate. The certificates can be signed by any trusted CA, including public or internal enterprise CAs. There is no requirement that the issuing authority be part of the organization running the BIG-IP.

Conclusion:
To support SSL re-encryption with a ServerSSL profile, pool members must present valid certificates signed by a trusted CA. This ensures secure end-to-end encryption and compliance with certificate validation mechanisms. Thus, the correct answer is C.

Question 8:

What is the correct sequence of actions when setting up a virtual server that uses an iRule based on the HTTP_REQUEST event?

A. Define profiles → Write the iRule → Create pools → Create the Virtual Server
B. Create the Virtual Server → Define pools → Write the iRule → Edit the Virtual Server
C. Build an HTTP profile → Define pools → Create the Virtual Server → Create the iRule
D. Create pools → Define an HTTP profile → Write the iRule → Set up the Virtual Server

Correct Answer: D

Explanation:

When configuring a virtual server that uses an iRule with the HTTP_REQUEST event in an F5 BIG-IP setup, it’s critical to follow a sequence that respects configuration dependencies. The iRule, which operates at Layer 7, can’t function correctly unless the system supports HTTP parsing. This requires an HTTP profile and a pool to direct traffic.

Let’s break down the correct order:

1. Create Pools:
   Pools are collections of backend servers that process requests. These must be defined first because they are required components of the virtual server. You cannot create a virtual server without assigning it a destination pool.

2. Create a Custom HTTP Profile:
   Since the iRule depends on HTTP events (like HTTP_REQUEST), the virtual server must include an HTTP profile. While you can use the default profile, creating a custom HTTP profile gives more control over behavior such as compression, caching, and header manipulation.

3. Write the iRule:
   Once the pool and HTTP profile exist, you can safely create the iRule. It can reference elements like pools or HTTP headers and should be designed knowing the traffic will be HTTP-based. If you create the iRule before the profile or pool, it may fail to bind properly.
   Create the Virtual Server:
   At this point, you can assemble the virtual server and attach all the components: pool, HTTP profile, and iRule. Doing it in this order ensures the system recognizes all references and allows seamless configuration.

Why other options are wrong:

• A. Suggests creating the iRule before the pools—this risks referencing non-existent elements.

• B. Begins with the Virtual Server creation—this is invalid because pools and profiles are prerequisites.

• C. Delays the iRule until after the Virtual Server—this causes additional steps like editing later, which is inefficient.

Conclusion:
To ensure successful deployment and functionality, the correct sequence is to create the pools, then the HTTP profile, then the iRule, and finally the virtual server that brings them all together. Therefore, the correct answer is D.

Question 9:

What is the primary function of a virtual server in the BIG-IP system?

A. It hosts the web application itself
B. It manages high availability between BIG-IP devices
C. It listens for client requests and directs them to a pool of servers
D. It stores SSL certificates and keys for encryption

Correct Answer: C

Explanation:

In the F5 BIG-IP system, a virtual server is one of the core components that handles incoming client traffic. It does not host applications or manage certificates directly; rather, it serves as the logical representation of a service on the network and functions as the traffic listener.

A virtual server is configured with:

• An IP address (called a VIP – Virtual IP)

• A port number (e.g., 80 for HTTP or 443 for HTTPS)

• A pool of backend servers to which it can direct traffic

When a client sends a request to a service (such as a web app), the virtual server receives that request. Based on its configuration, it decides how to handle the traffic—which pool to send it to, whether to apply SSL offloading, insert headers, or apply persistence rules.

Let’s review each option:

• A. Incorrect – The application itself runs on backend servers, not the virtual server.

• B. Incorrect – High availability is managed through device groups and failover configurations, not virtual servers.

• C. Correct – This is the main purpose of a virtual server: to receive and intelligently forward client traffic to pool members.

• D. Incorrect – SSL certificates and keys are part of SSL profiles, which may be associated with a virtual server but are not its primary function.

In summary, the virtual server is the entry point for client traffic in the BIG-IP architecture, and it determines how that traffic is processed and where it is sent. This makes C the correct and best answer.

Question 10:

Which component in the BIG-IP system defines a group of backend servers to which traffic can be distributed?

A. Node
B. Virtual Server
C. Pool
D. Monitor

Correct Answer: C

Explanation:

In F5’s BIG-IP system, a pool is a configuration object that contains a collection of backend servers—also called pool members—which deliver the actual services (such as web content, databases, or applications).

A pool allows BIG-IP to:

• Distribute client requests across multiple servers for load balancing

• Monitor the health of individual servers using monitors

• Apply load balancing algorithms (e.g., round robin, least connections, ratio-based)

• Remove unresponsive servers from the rotation

Let’s review each option:

• A. Node – A node refers to a single IP address on the network. It can exist independently or as a part of one or more pools. However, a node alone doesn’t perform load balancing.

• B. Virtual Server – As discussed in the previous question, a virtual server is the entry point for client traffic. It uses pools to determine where to send traffic but doesn’t define server groups itself.

• C. Pool (Correct) – A pool is the logical container that holds multiple servers (defined as pool members). It allows BIG-IP to distribute traffic based on various load balancing methods.

• D. Monitor – A monitor is a health check mechanism used to verify whether a pool member or node is responsive. It does not define groups of servers.

In practice, when configuring a virtual server, an administrator associates it with a pool so that traffic can be routed intelligently to the healthiest and most appropriate server. Pools can include members from the same subnet or different networks.

In conclusion, Option C is correct because pools are specifically designed to group multiple backend servers and manage how traffic is routed among them.