F5 F5CAB3 Dumps

To determine if an iRule is influencing traffic for a specific Virtual Server, the administrator must verify the association between the Virtual Server object and any applied scripts. In the BIG-IP Configuration Utility (GUI), this association is found under the Resources tab of the specific Virtual Server. While there is an "iRules" sub-menu under Local Traffic, checking the Virtual Server's Resources tab is the definitive way to see which specific rules are currently active and in what order they are being processed for that particular traffic flow.

From the Command Line Interface (CLI), the tmsh list /ltm virtual command provides a full text-based output of the virtual server's configuration. If iRules are applied, they will appear within a "rules { ... }" block in the command output. This is more effective than Option A, which only lists the contents of the iRule itself but does not show if or where it is applied. Option C is a common misconception; while some versions of the GUI have reorganized menus, the standard location for managing the association of profiles, policies, and iRules to a Virtual Server remains the "Resources" section. By identifying the applied iRule, an administrator can then review the script logic—often containing commands like pool or node—to see if it is overriding the default pool selection based on specific HTTP headers, URI paths, or client IP addresses.

For HTTP-based applications, cookie persistence is the most appropriate and commonly recommended persistence method.

According to the BIG-IP Administration: Data Plane Configuration documentation:

Cookie persistence inserts or uses an HTTP cookie to maintain session affinity.

It operates at Layer 7 (HTTP) and is application-aware.

It allows persistence to be maintained even when multiple clients are behind a NAT device.

Why the other options are incorrect:

A. Destination addressDestination address persistence is generally used for inbound traffic patterns such as firewall or proxy scenarios.

B. Hash persistenceHash persistence is less granular and not HTTP-specific.

C. SSL persistenceSSL persistence is typically used when SSL session IDs are reused and is less reliable than cookies for HTTP applications.

Correct Resolution:

Using cookie persistence ensures that HTTP web requests are consistently directed to the same pool member.

The configuration provided utilizes Priority Group Activation in conjunction with the min_active_members setting. Priority groups allow an administrator to define primary servers and "backup" servers within the same pool. The BIG-IP prioritizes traffic based on the assigned priority number, with the highest number receiving traffic first.

In this specific configuration, the priority 3 group is the primary group. Therefore, connections are first distributed to all pool members with priority 3 as long as they are available. The system will continue to use only the priority 3 group unless the number of available members in that group falls below the min_active_members value, which is set to 2.

If the priority 3 group has fewer than two active members, the BIG-IP "activates" the next available priority group (priority 2) and distributes traffic among the remaining members of priority 3 and all members of priority 2. This cascading logic continues down the list. Consequently, if both the priority 3 group and the priority 2 group have fewer than two members available, traffic is directed to the priority 1 group. This ensures that even in a multi-server failure scenario, the system has a last-resort group of servers to handle the traffic.

Option D is incorrect because if only one member of priority 3 goes down, there are still two members active (10.12.10.8 and 10.12.10.9). Since 2 is not less than the min_active_members threshold of 2, the priority 2 group will not yet be activated. Option B is incorrect because traffic flows from high priority to low priority, not the other way around.

The BIG-IP Configuration Utility (GUI) organizes information hierarchically to allow for granular management of application objects. A Pool is a collection of backend servers (pool members) that provide the same service. To verify the specific network parameters—such as the IP address and the service port—of the servers within a pool, the administrator must navigate to the specific pool's configuration.

The standard procedural path to verify this is Local Traffic > Pools: Pool List, where the administrator selects the specific pool name. Once inside the pool's configuration, the Members tab displays a list of all IP addresses and service ports associated with that pool. Under the "Service Port" column, the administrator can confirm if the member is listening on port 80 (HTTP).

Options A and B are incorrect for this specific verification task. While Nodes (Option A) show the health of a physical server, a node represents only an IP address and does not have a "Service Port" associated with it until it is defined as a pool member. Verifying the Health Monitor (Option B) would tell the administrator how the system is checking the member's status, but it does not definitively show the port on which the member is actually receiving application traffic. In a BIG-IP environment, a pool member is uniquely identified by the combination of its Node IP and its Service Port, and the Members tab is the primary interface for managing and auditing these specific member attributes.

X-Forwarded-For inserts the original client IP into HTTP headers while SNAT is enabled.

According to the provided exhibit, the "SSL Profile (Client)" section in the Virtual Server configuration is empty. For a BIG-IP system to process HTTPS traffic, it must act as an SSL/TLS endpoint. This process, known as SSL Termination or SSL Offload, requires the assignment of a Client SSL Profile to the Virtual Server. Without this profile, the BIG-IP does not have the necessary certificate and private key information to perform the SSL handshake with the client's browser. Consequently, when a user attempts to connect via HTTPS, the TCP connection may establish, but the SSL handshake will fail because the BIG-IP will not know how to decrypt the incoming encrypted packets.

A Client SSL profile defines the ciphers, certificates, and keys that the BIG-IP uses to communicate securely with the client. In a standard HTTPS deployment, the BIG-IP decrypts the traffic and can then send it to the backend pool members either as plain text (header insertion/manipulation) or re-encrypt it using a Server SSL profile. While a Server SSL profile (Option C) is needed if the backend servers themselves require HTTPS, the initial failure for a user reaching a Virtual Server is almost always the lack of a Client SSL profile to terminate the user's connection. Changing the Service Port to HTTP (Option D) would be incorrect because the goal is to handle HTTPS traffic (typically port 443). Assigning the "clientssl" or a custom client-side profile from the "Available" list to the "Selected" list in the GUI is the mandatory step to make the Virtual Server operational for secure web traffic.

Similar to the logic required for managing multi-service backend environments, the issue described—where servers hosting multiple protocols like FTP and HTTP are experiencing uneven distribution—stems from the BIG-IP's default behavior of treating each pool independently. If the administrator uses a member-based load balancing method, the BIG-IP distributes HTTP traffic regardless of how much FTP traffic that same physical server is currently processing.

To resolve this, the administrator must utilize the Least Connections (Node) method. By switching both the HTTP and FTP pools to this algorithm, the BIG-IP begins to make load balancing decisions based on the total combined connection count for the IP address of each server. When a new HTTP request arrives, the BIG-IP checks which server has the fewest total connections (including existing FTP sessions). This prevents a server that is already busy with long-lived FTP transfers from being overwhelmed by a sudden burst of HTTP requests.

Ratio methods (Options A and C) are static and rely on the administrator manually assigning weights to servers based on their perceived capacity; they do not adapt to real-time fluctuations in traffic volume across different pools. Least Connections (Member) (Option B) remains blind to the "cross-pool" traffic on the same hardware. Only the Node-based Least Connections approach provides the global visibility necessary to "even out" the total resource utilization across servers supporting multiple distinct applications.

In BIG-IP configuration, health monitors can be applied at three distinct levels: the node, the pool, or the individual pool member. To ensure that a specific application service—in this case, a database service on port 1521—is functioning correctly for the entire pool, the administrator should apply the monitor at the pool level. Navigating to Local Traffic > Pools > DB.Pool > Properties allows the administrator to select one or more monitors from the "Available" list and move them to the "Active" list.

Applying a monitor at the pool property level ensures that the BIG-IP checks the health of every member assigned to that pool using the same logic. If a database-specific monitor (such as a TCP handshake or an Oracle/SQL check) fails for a specific member, the BIG-IP marks that member as "offline" for that specific pool, preventing new connections from being sent to it. While monitors can be applied to Pool Members (Option D) to give different members unique monitoring logic, it is more administratively efficient to apply it to the pool properties when all servers are expected to behave identically. Applying it to Nodes (Option C) would only verify that the IP address is up (typically via ICMP), which does not guarantee that the database service on port 1521 is actually responding. Finally, Profiles (Option A) are used to define how traffic is handled once it is accepted by a Virtual Server, not for the proactive health checking of backend resources. Therefore, the pool properties page is the standard location for configuring service-specific availability requirements.

BIG-IP provides several built-in TCP profiles optimized for different traffic patterns and network conditions. When attempting to improve general TCP performance, the recommended starting point is f5-tcp-progressive.

According to the BIG-IP Administration: Data Plane Configuration documentation:

f5-tcp-progressive is designed as a balanced, general-purpose TCP optimization profile.

It dynamically adjusts TCP behavior to improve throughput and latency for most enterprise applications.

It is the recommended first-choice profile when tuning TCP performance before moving to more specialized profiles.

Why the other options are incorrect:

A. f5-tcp-legacyThis profile exists for backward compatibility and does not include modern TCP optimizations.

C. f5-tcp-mobileThis profile is optimized specifically for high-latency, lossy mobile networks and is not suitable for general-purpose environments.

D. No optionBIG-IP explicitly provides built-in TCP profiles for performance tuning; using none would forgo optimization opportunities.

Correct Resolution:

The administrator should first apply f5-tcp-progressive to evaluate potential TCP performance improvements before considering more specialized profiles.

Slow Ramp Time prevents new members from being overwhelmed immediately after activation.

In the F5 BIG-IP ecosystem, a standard ICMP health monitor functions by sending an ICMP echo request to a target node and expecting an ICMP echo reply within a specified timeout period. When a node is marked "DOWN" despite the backend server being configured to respond to ICMP, the issue typically lies in the network path or the specific packet exchange between the BIG-IP's self IP and the node's IP. Running a tcpdump is the most effective next step because it provides a real-time packet capture of the actual monitor traffic leaving the BIG-IP and any return traffic coming back from the server. This allows the administrator to verify if the BIG-IP is actually sending the echo request, if the request is reaching the server, and if the server is indeed replying or if the reply is being dropped by an intermediate firewall or a security policy.

While other tools have their place, they are inappropriate for this specific layer 3/4 connectivity issue. A qkview is a comprehensive diagnostic file used primarily for F5 Support to analyze the entire system's state but is overkill for initial connectivity troubleshooting. An ssldump is used for inspecting SSL/TLS handshakes and encrypted payloads, which is irrelevant for a non-encrypted ICMP monitor. A curl command is a tool for testing HTTP/HTTPS application-level responses; it cannot be used to troubleshoot ICMP (ping) connectivity directly. By using tcpdump -ni host , the administrator can see the ICMP "type 8" (request) and "type 0" (reply) packets, immediately identifying if the monitor failure is due to a "Destination Unreachable" message or a simple lack of response, thereby pinpointing the root cause in the data plane.

Connection rate limiting controls how many new connections per second are accepted, protecting backend resources.

In this scenario, each backend node (server) hosts multiple services and is referenced by multiple pools and virtual servers. The goal is to ensure an equal number of total connections per backend server, regardless of how many pool members (services/ports) exist on that server.

According to the BIG-IP Administration: Data Plane Configuration documentation:

Least Connections (node) tracks the total number of active connections to a node across all pool members and services.

This algorithm ensures load distribution is balanced at the server level, not just at the individual service (member) level.

It is specifically recommended when:

Multiple pool members exist on the same backend server

Multiple virtual servers reference the same backend servers

Why the other options are incorrect:

B. Predictive (member)Predictive algorithms are advanced and traffic-pattern based, but they operate at the member level and do not guarantee equal connections per server.

C. Least Connections (member)This balances connections per pool member, which can overload a server hosting multiple members while still appearing “balanced” per member.

D. Predictive (node)Although node-aware, predictive algorithms are less deterministic and not the best choice when strict equality of connections is required.

Correct Resolution:

Using Least Connections (node) ensures that each backend server carries an equal connection load across all services and pools.

When dealing with heterogeneous server hardware where some servers are more powerful than others, a dynamic load balancing method that accounts for both current load and server capacity is required. The Weighted Least Connections (member) method is the most appropriate choice. This method works by tracking the number of active connections to each pool member and then "weighting" that number based on a user-defined Ratio value assigned to the member. For example, the administrator can assign a higher Ratio to the three newer, more powerful servers and a lower Ratio to the two older servers. The BIG-IP then uses a formula to calculate which server should receive the next connection, ensuring that the newer servers handle a proportionately larger share of the total concurrent connections.

Standard Round Robin (Option C) would be ineffective because it distributes connections strictly sequentially (1, 2, 3, 4, 5) without regard for the servers' capacity or current load, which would eventually overwhelm the older servers. Least Connections (member) (Option D) is better than Round Robin because it picks the server with the fewest active connections, but it still assumes all servers are equal; it would try to keep the connection counts identical across all 5 servers, which would still stress the older hardware more than the new. Global Availability (Option B) is a GSLB (DNS-based) method used for multi-site redundancy, not for local pool member load balancing. By using Weighted Least Connections, the administrator achieves a balance where the more capable servers take the brunt of the work while the older servers are utilized only to their specific safe capacity.

In a default BIG-IP configuration, the system utilizes the Load Balancing Method (typically Round Robin) to distribute each new connection across available pool members. However, the introduction of a persistence profile fundamentally changes this behavior. Persistence (also known as "stickiness") ensures that once a client has been load balanced to a specific pool member, all subsequent requests from that same client during a defined session or timeout period are directed to that same member, bypassing the standard load balancing algorithm. This is critical for applications that maintain state, such as shopping carts or authenticated sessions, where moving a user to a different server would result in a loss of session data.

While other options affect traffic handling, they do not "alter" the fundamental load balancing decision in the same way. A OneConnect profile (Option A) optimizes connection management by pooling idle server-side connections; while it changes how connections are reused, the initial load balancing decision still follows the configured method. A fallback host (Option C) is only utilized when the primary pool is unavailable, and since the question states all pool members are online, it remains inactive. SNAT Automap (Option D) changes the source IP address of the packet as it exits the BIG-IP toward the server to ensure return traffic passes back through the ADC, but it does not dictate which server is chosen for the request. Therefore, the persistence profile is the primary configuration element that overrides the load balancing algorithm to maintain a client-to-server relationship.

The issue of "lost shopping carts" in an ecommerce environment is a classic symptom of a missing or improperly configured Persistence Profile. In modern web applications, session data—such as items added to a cart—is often stored locally on the specific web server that initially handled the user's request. If the BIG-IP system load balances a user's subsequent request (like clicking "Checkout") to a different server among the 50 webservers, the new server will not have the session data, and the user will appear to have an empty cart.

While Least Connections (node) is an efficient load balancing algorithm, it makes a new decision for every connection unless persistence is enabled. To resolve this, the administrator must implement a persistence mechanism. HTTP Cookie Persistence (Option A) is the industry standard for web applications. By assigning a cookie persistence profile to the Virtual Server, the BIG-IP inserts a unique cookie into the HTTP response. When the user's browser returns that cookie in future requests, the BIG-IP identifies the specific server that handled the first request and consistently directs the user back to that same server for the duration of their session.

Sip_info (Option B) is a persistence method for VOIP traffic and is not applicable to web traffic. Ratio load balancing (Options C and D) merely changes the distribution frequency but still does not guarantee that a specific user will stay on the same server across multiple requests. Therefore, adding a cookie persistence profile is the direct procedural fix to maintain session state and ensure ecommerce functionality.

Slow Ramp Time prevents new pool members from receiving a full share of traffic immediately, allowing applications to warm up gradually.

Standard DNS queries use UDP. Configuring the Virtual Server for TCP causes DNS traffic to fail.

A Performance (Layer 4) virtual server does not inspect or process application-layer data such as HTTP headers or cookies. Therefore, only Layer 4–compatible persistence methods can be used.

According to the BIG-IP Administration: Data Plane Configuration documentation:

Source Address Affinity persistence operates at Layer 4 and uses the client IP address to maintain session persistence.

It is fully compatible with Performance (Layer 4) virtual servers.

It works regardless of encryption, making it suitable for TLS-secured applications.

Why the other options are incorrect:

B. Cookie persistenceRequires an HTTP profile and Layer 7 inspection, which is not supported on Performance virtual servers.

C. Microsoft RDP persistenceIs protocol-specific and not applicable to web-based TLS traffic.

D. Host persistenceRequires HTTP host header inspection, which is not available at Layer 4.

Correct Resolution:

Source Address Affinity persistence is the appropriate choice for maintaining persistence on a Performance (Layer 4) virtual server handling TLS traffic.

Below is Batch 1 (Questions 1–10) extracted only from your uploaded document that are directly related to BIG-IP Administration: Data Plane Configuration topics (Virtual Servers, Pools, Load Balancing, Monitors, Persistence, SNAT, Profiles).

I have excluded system-only, licensing, support, hardware, HA management-only, and admin UI questions that are not Data Plane–focused.

Source: Your uploaded TMOS Administration v2.0 document

✅ BATCH 1 (10 Questions)

DNS traffic is primarily transported using UDP port 53. In the exhibit, the Virtual Server is configured with the Protocol set to TCP, which prevents standard DNS queries from being processed correctly. BIG-IP Virtual Servers must be configured with the correct Layer 4 protocol to match the application traffic they are handling.

According to the BIG-IP Administration: Data Plane Configuration documentation:

The Protocol setting on a Virtual Server defines whether traffic is processed as TCP, UDP, or another supported transport protocol.

Standard DNS queries and responses use UDP, while TCP is only required for DNS zone transfers (AXFR) or exceptionally large responses.

When a DNS Virtual Server is incorrectly configured with TCP, UDP-based DNS queries are dropped, causing all requests to fail.

Why the other options are incorrect:

A. Protocol profile (Client) to DNS_OPTIMIZEDA DNS profile enhances DNS functionality but does not correct an incorrect transport protocol configuration.

B. Type to Performance (HTTP)Performance (HTTP) Virtual Servers are designed for HTTP traffic and are not suitable for DNS services.

C. Source Address to 192.168.10.0/24The existing source IPs already fall within the allowed range, so this setting does not address the failure.

Correct Resolution:

Changing the Protocol to UDP aligns the Virtual Server with standard DNS transport requirements, allowing DNS queries to be successfully processed and load-balanced.

SNAT Automap is a common configuration that replaces the client's original source IP address with one of the BIG-IP's self IP addresses. This ensures that the backend servers send return traffic back through the BIG-IP, which is necessary for the ADC to process the traffic correctly. However, a side effect of SNAT is that the backend servers only see the BIG-IP's IP in their logs, losing visibility into the true identity of the client.

To resolve this while still using SNAT for routing purposes, the administrator must configure the BIG-IP to "pass" the client's IP address at the application layer. This is achieved by using an HTTP Profile with the Insert X-Forwarded-For setting enabled. When this profile is applied to the Virtual Server, the BIG-IP intercepts the HTTP request, adds a header (X-Forwarded-For) containing the client's original IP, and then forwards the modified request to the server. The backend web server can then be configured to read this header and log the original client IP instead of the BIG-IP's SNAT address.

Other options are incorrect for this requirement. Performance (HTTP) (Option A) is a virtual server type optimized for speed but often lacks the full Layer 7 header manipulation capabilities of a Standard Virtual Server. SNAT Pool with the client IP (Option C) is technically impossible as SNAT pools use static, pre-defined IPs. There is no such thing as an HTTP Transparent profile (Option D) in standard BIG-IP administration for this purpose. The X-Forwarded-For header insertion within the HTTP profile is the standard procedural method for maintaining client visibility in SNAT-enabled environments.

WAN-optimized TCP profiles improve performance for high-latency Internet clients, while LAN profiles are optimal for backend servers.