What is the main use of port 80?

Port 80 is primarily used for standard web traffic, specifically the Hypertext Transfer Protocol (HTTP). When a user accesses a website without specifying a secure connection (HTTPS), the web server typically communicates on port 80. This protocol facilitates the transfer of web pages, images, and other resources needed to render websites in a browser.

In the context of network communications, this standard allows for the retrieval of hypertext documents from web servers, which is fundamental to browsing the internet. Given its designation for this common data transmission, port 80 serves as the backbone of unencrypted web traffic.

The other options relate to different protocols and purposes. For example, email transmission generally occurs over ports like 25 for SMTP (Simple Mail Transfer Protocol) or 110 for POP3 (Post Office Protocol). Secure communications are typically conducted over port 443, which is associated with HTTPS, the secure version of HTTP. File transfers often use protocols such as FTP (File Transfer Protocol) that typically operate on ports 20 and 21. Understanding these distinctions is crucial for comprehending how different services operate on specific ports within a network.