Which protocol operates on TCP port 80?

The protocol that operates on TCP port 80 is HTTP, which stands for Hypertext Transfer Protocol. This protocol is fundamental for transmitting data over the web, as it dictates how messages are formatted and transmitted. When a web browser requests a web page, it uses HTTP to request the data from a web server, which then responds by sending the requested HTML web page back to the browser.

This relationship is crucial for the functionality of the Internet, as it establishes a framework for communication between clients (web browsers) and servers. The use of TCP port 80 specifically designates the conventional port for this type of traffic, allowing for standardized communication procedures.

Other protocols serve different purposes and utilize other ports. For example, SMTP (Simple Mail Transfer Protocol) operates on TCP port 25, primarily used for sending emails. DNS (Domain Name System), which translates domain names to IP addresses, uses port 53. FTP (File Transfer Protocol), responsible for file transfers, typically operates on ports 21 and 20. Understanding the specific port allocations is essential for network configuration and management, as it helps in setting up firewalls and ensuring appropriate traffic flows within networks.