What parameter identifies the application when a client requests a service from a remote server?

What parameter identifies the application when a client requests a service from a remote server?

• A. Destination port number
• B. Source IP address
• C. MAC address
• D. Frame length

Answer: (A)

The ability to pick which service or application handles incoming data on the destination host comes from the destination port in the transport layer header (TCP or UDP). Each service listens on a specific port, so when a client sends a request, the destination port tells the receiving system which process to deliver the data to—examples are port 80 for HTTP and port 443 for HTTPS. The source IP address identifies who sent the request, the MAC address is used for local network addressing, and the frame length is just the size of the data frame, not the service being requested.

The ability to pick which service or application handles incoming data on the destination host comes from the destination port in the transport layer header (TCP or UDP). Each service listens on a specific port, so when a client sends a request, the destination port tells the receiving system which process to deliver the data to—examples are port 80 for HTTP and port 443 for HTTPS. The source IP address identifies who sent the request, the MAC address is used for local network addressing, and the frame length is just the size of the data frame, not the service being requested.