F5 Networks F5CAB5 Exam Dumps

The issue is caused by the Source Address restriction configured on the virtual server.

Source Filter: The configuration contains the line source 192.168.0.0/16. This acts as an implicit Access Control List (ACL). The virtual server will only accept and process TCP connections if the client's source IP address falls within the 192.168.x.x range.

Why Ping Works: ICMP (Ping) is handled by the Virtual Address object, not the Virtual Server object. Unless ICMP is specifically disabled on the Virtual Address, it will respond to pings from any subnet, even if the Virtual Server itself is restricted by a source filter or is even disabled.

Evaluation of Other Options:

Disabled (Option A): If the VS were disabled, the configuration would typically show disabled or state down, and the symptoms would be similar, but the source filter is a more specific 'misconfiguration' in this context.

Port 80 (Option C): The configuration destination 10.99.20.50:http explicitly confirms it is listening on port 80.

Unallowed Subnet: If a client from a different network (e.g., 10.10.1.5) tries to connect, the BIG-IP will silently drop the connection or send a reset because it does not match the defined source criteria.

BIG-IP status icons provide immediate visual feedback regarding the state of an object based on its availability and enabled/disabled status.

Color (Black): The color black indicates that an object has been manually Disabled by an administrator.

Shape (Circle): The circular shape indicates that the object is Available (i.e., its health monitors are passing).

Scenario Result: Since the virtual server is manually disabled (Black) but its associated pool has a working health monitor that is currently passing (Circle), the resulting icon is a Black Circle.

To ensure a support case is processed and routed efficiently, F5 specifies a mandatory set of baseline information.

Serial Number: Required to verify the support contract and entitlement level for the hardware or virtual edition.

QKView: This is described as the 'first and most important thing to have when opening a case'. It provides the F5 Support Engineer with the necessary diagnostic data to understand the system's current state and resource utilization.

Problem Description: A precise description of the issue, including symptoms, when the problem started, and the business impact, is critical for routing the case to the correct technical team.

Contact Info: Accurate contact information for the individual who will be working on the ticket with F5.

Comparison: While packet captures (Option A) or UCS files (Option B) are often useful, they are not strictly required for the initial opening of all support tickets; however, a QKView is considered a primary prerequisite for technical analysis.

To manually verify a health monitor's 'Send String' from the BIG-IP command line, the curl utility is the preferred tool because it allows for custom header insertion.

Matching the Monitor String: The monitor string requires an HTTP/1.1 request which must include a 'Host' header. Option A correctly uses the --header (or -H) flag to pass Host: www.example.com to the specific IP and port of the pool member.

Troubleshooting Logic: If curl --header 'Host: www.example.com' 'http://10.10.3.75:8080/' returns a '200 OK' but the BIG-IP monitor still shows 'Down,' the administrator should check if the Receive String in the monitor configuration matches the output provided by curl.

Invalid Syntax: Option D is incorrect because it tries to append the hostname to the URI path, which the web server will likely reject with a '404 Not Found'. tracepath (Options B and C) is a path discovery tool similar to traceroute and cannot validate HTTP response content.

In BIG-IP TMOS administration, the 'Forwarding (IP)' virtual server type is unique because it is designed to act as a high-performance router rather than a typical load balancer. Unlike a 'Standard' virtual server, which terminates a connection and directs it to a specific pool of members, a Forwarding (IP) virtual server is intended to forward packets based on the system's routing table. Consequently, the configuration for this type of virtual server explicitly removes the option to associate a default pool. If an administrator is troubleshooting a scenario where they cannot assign a pool to a virtual server, they must verify if the type was accidentally set to Forwarding (IP). This type is most commonly used for outbound internet traffic (outbound SNAT) or to allow the BIG-IP to serve as a gateway between internal subnets. Identifying this constraint is vital for troubleshooting configuration errors where an administrator expects the system to load balance traffic but finds the pool association settings are grayed out or unavailable in the Configuration Utility.