iSACA Cybersecurity Fundamentals Certification Practice Exam

What are dynamic/private ports used for?

1. Only system processes

2. Ordinary user processes

3. Protocols that require static assignments

4. Dynamic assignments where they are not preassigned

The correct answer is: Dynamic assignments where they are not preassigned

Dynamic or private ports are utilized for dynamic assignments where they are not preassigned. These ports fall within the range of 49152 to 65535, which is designated for ephemeral use by client applications on a temporary basis. When a client application needs to initiate communication with a server, it typically requests a dynamic port which is assigned by the operating system, allowing for a unique connection without requiring a static port number. This flexibility is critical in ensuring that applications can establish network connections without the constraints of pre-assigned port numbers, preventing conflicts and allowing multiple applications on the same host to communicate over the network simultaneously. This makes dynamic ports ideal for scenarios such as web browsing or accessing various services that require short-lived connections. In contrast, the other options suggest limitations on the use of dynamic ports. For instance, if they were only for system processes or ordinary user processes, it would imply that their use is restricted, which contradicts their inherent purpose of supporting dynamic and more generalized assignments. Similarly, protocols requiring static assignments specifically refer to fixed port numbers that are not meant for dynamic allocation, further emphasizing the unique characteristic of dynamic ports.