Pass the F5-CA F5CAB3 Questions and answers with ExamsMirror

With manual resume enabled, BIG-IP does not automatically return a pool member to service after recovery. The member remains offline until manually re-enabled.

A red diamond indicates the Virtual Server is enabled but unavailable due to all pool members being down.

DNS traffic is primarily transported usingUDP port 53. In the exhibit, the Virtual Server is configured with theProtocol 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 theBIG-IP Administration: Data Plane Configurationdocumentation:

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

Standard DNS queries and responses useUDP, whileTCP 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 theProtocol to UDPaligns the Virtual Server with standard DNS transport requirements, allowing DNS queries to be successfully processed and load-balanced.

SSH is a TCP-based service. A TCP monitor validates service availability without requiring application-layer inspection.

SSH is aLayer 4 TCP-based protocolthat operates onTCP port 22and doesnot use HTTPin any capacity. In the exhibit, the Virtual Server is configured with anHTTP Profile applied, which is inappropriate for SSH traffic and causes connection failures.

According to theBIG-IP Administration: Data Plane Configurationdocumentation:

AnHTTP profile must only be applied to Virtual Servers handling HTTP or HTTPS traffic.

When an HTTP profile is attached, BIG-IP expects HTTP headers and attempts to parse application-layer data.

Non-HTTP protocols such asSSH, FTP (control), SMTP, and other raw TCP serviceswill fail if an HTTP profile is enabled.

Why the other options are incorrect:

A. Set Protocol to UDPSSH usesTCP, not UDP. Changing the protocol would break SSH entirely.

B. Set Source Address to 10.1.1.2The source address setting controls client access restrictions and is unrelated to protocol parsing issues.

C. Set Destination Address/Mask to 0.0.0.0/0The destination address is already valid for a specific SSH service and does not impact protocol handling.

Correct Resolution:

The BIG-IP Administrator shouldremove the HTTP Profile (set it to None)so the Virtual Server functions as a pure Layer 4 TCP service, allowing SSH connections to pass through successfully.

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

According to theBIG-IP Administration: Data Plane Configurationdocumentation:

Cookie persistenceinserts or uses an HTTP cookie to maintain session affinity.

It operates atLayer 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:

Usingcookie persistenceensures that HTTP web requests are consistently directed to the same pool member.

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

Forwarding (IP) virtual servers forward traffic based on routing decisions and do not use pools or pool members.

When the connection limit is reached, BIG-IP resets new connections, even if pool members are healthy.

SSH is a TCP Layer 4 protocol. Applying an HTTP profile causes BIG-IP to expect HTTP headers, breaking SSH sessions. Removing the HTTP profile allows raw TCP forwarding.