F5CAB5 BIG-IP Administration Support and Troubleshooting (F5CAB5) exam Questions and Answers

To collect application-layer details such asHTTP status codes(200, 404, 500, etc.) andHTTP methods(GET, POST, PUT, DELETE), the BIG-IP system must use a profile designed for traffic visibility and reporting rather than basic traffic handling. TheAnalytics profile (Option C)is the correct choice because it is specifically designed to collect, store, and present detailed statistics about HTTP and TCP traffic passing through a virtual server.

When an Analytics profile is attached to a virtual server, BIG-IP can record metrics such as HTTP response codes, request methods, URI paths, latency, throughput, and client-side/server-side performance data. These statistics are then accessible through the BIG-IP GUI underStatistics → Analytics, allowing administrators to validate application behavior and troubleshoot performance or functional issues.

TheHTTP profile (Option B)enables HTTP protocol awareness and features like header insertion and compression, but it does not provide historical or statistical reporting of HTTP methods and response codes.Request Adapt (Option A)is used for ICAP-based content adaptation, not visibility.Statistics (Option D)is not a standalone profile and does not provide HTTP-level insight.

Therefore, the Analytics profile is the only default profile that fulfills this requirement.

Comprehensive and Detailed Explanation From BIG-IP Administration Support and Troubleshooting documents:When troubleshooting intermittent connection resets on a "busy" Virtual Server, the administrator must examine the configured thresholds62. A "Connection Limit" is a hard cap on the number of concurrent connections a Virtual Server or pool member can handle63. If this limit is set too low, the BIG-IP will reset any new connection attempts once the threshold is reached64. The key indicator in this scenario is that the problem only affects "some users" and happens when the server is "busy," suggesting that the system is hitting a capacity ceiling rather than suffering from a persistent configuration error65. Unlike a missing SSL profile, which would likely cause all connections to fail, or a "Connection Rate Limit," which throttles how fast connections arrive, a "Connection Limit" focuses on the total volume66. Identifying this as the cause requires reviewing the Virtual Server's statistics to see if the "Current Connections" count is consistently peaking at the configured limit value.

Comprehensive and Detailed Explanation From BIG-IP Administration Support and Troubleshooting documents: The "Manual Resume" feature is a safety mechanism used when a pool is not working as expected due to flapping services or unstable backend applications. Normally, when a health monitor fails, the pool member is marked "Offline" (Red), and when the monitor passes, it automatically returns to "Available" (Green)47. However, if "Manual Resume" is enabled, the BIG-IP will not automatically put the member back into rotation after a failure48. Even if the health check begins to pass again, the member remains in an "Offline (Disabled)" state49. This requires an administrator to manually intervene and re-enable the member. This is a common point of confusion when troubleshooting; a member may show passing health checks but still not receive traffic because it is waiting for a manual administrative "resume" command. This feature is intended to prevent "unhealthy" servers from receiving traffic until an engineer has confirmed the root cause of the initial failure was resolved.

Comprehensive and Detailed 150 to 250 Words Explanation From BIG-IP Administration, Support, and Troubleshooting Documents:

AQKViewfile is the primary diagnostic support bundle used by F5 Support to troubleshoot BIG-IP system issues. It contains comprehensive system information, including running configuration, licensing details, module provisioning, hardware status, software versions, log files, statistics, and the output of numerous diagnostic commands. Generating a QKView is a standard and recommended first step when investigating performance problems, configuration issues, or when opening a support case with F5.

In the BIG-IP Configuration Utility (GUI), the correct and supported location to generate a QKView isSystem > Support. This menu is specifically designed for support and troubleshooting operations. From this section, administrators can generate a QKView file, monitor its creation progress, download it locally, or upload it directly to F5 iHealth for automated analysis. This workflow is clearly documented in BIG-IP Administration and Support guides and aligns with F5 best practices.

The other menu options are not appropriate:

System > Configurationis used for system-wide settings such as DNS, NTP, and device identity.

System > Archiveis used to create UCS backup files, which are configuration backups, not diagnostic bundles.

System > Logsis used only for viewing system logs, not generating support files.

Therefore,System > Supportis the correct and only valid answer.

Troubleshooting failed SSL handshakes involves interpreting the resource limits defined by the system's license8888. The log message SSL transaction (TPS) rate limit reached indicates the BIG-IP is dropping SSL connections because it has exceeded its licensed "Transactions Per Second" capacity. When analyzing stats to determine the correct license level, the administrator must focus on "Client-side" SSL TPS. This represents the initial encrypted handshakes between users and the BIG-IP virtual servers91. In this scenario, the peak client-side demand is 1200 TPS. While the 800 server-side transactions represent re-encryption toward the backend, F5's primary SSL TPS license limits typically apply to the client-facing side of the traffic flow. Therefore, to resolve the intermittent connectivity issues and ensure the virtual server works reliably during peaks, the license must be upgraded to at least 1200 TPS949596969696.9798Confirming this peak via statistics andcomparing it to the current license is a standard troubleshooting step for SSL performance issues.

According toofficial F5 documentation (K52015891 – Troubleshooting BIG-IP power supply issues),hardware-related alerts for power supplies, fans, and chassis components are logged in /var/log/ltm.

When a BIG-IP device experiences a power supply issue—such as failure, intermittent outages, or fan-related faults—the system generates alerts through internal platform monitoring services. These alerts are written to the/var/log/ltmfile and often appear with messages similar to:

Chassis power supply 2 has experienced an issue. Status is as follows: FAN=bad; STATUS=bad.

This makes /var/log/ltm theauthoritative log filefor identifying and verifying power supply and chassis-related problems on BIG-IP systems.

The other log files are not appropriate for this purpose:

/var/log/daemon.logcontains general daemon messages but isnot the primary sourcefor chassis hardware alerts.

/var/log/kern.loglogs kernel-level events, not platform power status.

/var/log/auditrecords administrative actions and configuration changes.

Conclusion:

Per F5-supported guidance, when suspecting power supply outages or chassis hardware issues, the BIG-IP Administrator shouldalways check /var/log/ltm first.

In complex network environments, "SNAT Automap" is frequently used to ensure that backend servers send return traffic through the BIG-IP. However, SNAT hides the original client's IP address, replacing it with the BIG-IP's self-IP. When interpreting traffic flow for security or logging purposes, backend servers often need that original IP. To resolve this without breaking the network-layer routing provided by SNAT, the administrator should apply an HTTP profile to the virtual server and enable the "Insert X-Forwarded-For" option. When this is enabled, the BIG-IP inserts a standard HTTP header containing the client's original IP address before forwarding the request to the pool member. This troubleshooting method allows the backend application to log the actual user's identity while maintaining a functional L3/L4 traffic flow where the server responds to the BIG-IP's local address. This is a standard troubleshooting solution for "web server not working as expected" scenarios where applica8tion logic depends on knowing the geography or specific identity of the connecting user.

To successfully performSSL offload and re-encryptionon a BIG-IP system, the virtual server must be configured withboth a Client SSL profile and a Server SSL profile. The Client SSL profile enables BIG-IP to decrypt inbound HTTPS traffic from clients, while the Server SSL profile is required tore-encrypt traffic before forwarding it to the pool members.

From the exhibit, the virtual server has aClient SSL profile configured, which allows BIG-IP to accept HTTPS connections from clients. However, there isno Server SSL profile attached, meaning BIG-IP attempts to sendunencrypted HTTP trafficto pool members listening on HTTPS (port 443). This protocol mismatch causes the server-side SSL handshake to fail, resulting in users being unable to connect to the application.

This behavior is well documented in BIG-IP SSL troubleshooting guides: when backend servers expect HTTPS, a Server SSL profile is mandatory to establish a secure connection from BIG-IP to the pool members.

The other options are incorrect:

Removing the Client SSL profile (Option A) would break client-side HTTPS.

The server-side TCP profile (Option B) is unrelated to SSL encryption.

Forward Proxy (Option C) is only used for outbound SSL inspection scenarios.

Therefore, configuring anSSL Profile (Server)is the correct and required solution.

Troubleshooting SSL connection resets often involves verifying license limits against actual resource utilization. F5 devices use a "Transactions Per Second" (TPS) license to control the amount of SSL processing the device can handle. The log entry SSL transaction (TPS) rate limit reached is a clear indicator that the traffic volume has exceeded the licensed capacity. When determining the necessary license level, it is important to know that F5 primarily licenses and limits the "Client-side" SSL TPS—which represents the encrypted connections between the users and the virtual servers. In this specific scenario, the peak demand reached 1200 client-side transactions per second. Although there were also 800 server-side transactions (re-encryption from the BIG-IP to the pool), these typically do not count against the primary TPS license limit in the same manner. Therefore, to ensure that the virtual server works as expected during peak load, the administrator must upgrade the license to at least 1200 TPS. This troubleshooting process links system log errors to license-enforced resource constraints.