CREST Practitioner Security Analyst (CPSA) Practice 2025 – All-in-One Guide to Mastering Exam Success!

The port number in networking serves as an identifier for service endpoints, which means it is used to distinguish different services or applications running on a device or server. Each service that communicates over the internet or a network is associated with a specific port number, allowing the network stack to direct incoming and outgoing packets to the appropriate application. For instance, web traffic typically uses port 80 for HTTP and port 443 for HTTPS. This identification helps ensure that the correct application receives the communication intended for it without confusion or overlap with other services that may also be running on the same device.

In contrast, other options relate to different aspects of networking and do not accurately describe the role of port numbers. The type of encryption used pertains to security protocols but is not represented by port numbers. Data compression levels refer to how data is reduced in size for transmission, without any direct connection to port identification. Similarly, network bandwidth allocation deals with how much data can be transferred in a given time frame but is also unrelated to the function of port numbers in distinguishing service endpoints.