A client packet is received by a server. The packet has a destination port number of 80. What service is the client requesting?

A client packet is received by a server. The packet has a destination port number of 80. What service is the client requesting?

• A. FTP
• B. SMTP
• C. HTTP
• D. DNS

Answer: (C)

When a client packet is received by a server with a destination port number of 80, the service being requested is HTTP (Hypertext Transfer Protocol). HTTP is the foundational protocol used for transmitting hypertext (web pages) over the internet. Web browsers use this protocol to request web resources such as HTML pages, images, and other content that make up websites. Ports are essential components of networking, acting as virtual channels that allow different types of traffic to be managed over a network. Port number 80 is well established as the standard port for HTTP traffic, which is why any packet arriving at that port signals a request for web-related services. Other options represent different services that use different standard port numbers. For instance, FTP (File Transfer Protocol) typically uses port 21, SMTP (Simple Mail Transfer Protocol) uses port 25, and DNS (Domain Name System) usually operates over port 53. Each of these services has its designated ports, and a packet arriving at one of these ports indicates a request specific to that service. Therefore, the presence of a destination port number of 80 clearly indicates that the client is requesting an HTTP service.

When a client packet is received by a server with a destination port number of 80, the service being requested is HTTP (Hypertext Transfer Protocol). HTTP is the foundational protocol used for transmitting hypertext (web pages) over the internet. Web browsers use this protocol to request web resources such as HTML pages, images, and other content that make up websites.

Ports are essential components of networking, acting as virtual channels that allow different types of traffic to be managed over a network. Port number 80 is well established as the standard port for HTTP traffic, which is why any packet arriving at that port signals a request for web-related services.

Other options represent different services that use different standard port numbers. For instance, FTP (File Transfer Protocol) typically uses port 21, SMTP (Simple Mail Transfer Protocol) uses port 25, and DNS (Domain Name System) usually operates over port 53. Each of these services has its designated ports, and a packet arriving at one of these ports indicates a request specific to that service. Therefore, the presence of a destination port number of 80 clearly indicates that the client is requesting an HTTP service.