What is the default HTTP port number used for web traffic?

The default HTTP port number used for web traffic is 80. This is a standard defined by the Internet Assigned Numbers Authority (IANA) for web services using the Hypertext Transfer Protocol (HTTP). When a web browser attempts to access a website without a specified port number in the URL, it automatically assumes that the server listens for requests on port 80.

This standardization facilitates communication across the web, allowing various clients and servers to connect seamlessly using a common protocol. The use of port 80 for HTTP is so ubiquitous that many users and developers do not need to specify it explicitly in their URLs, making it an essential aspect of web traffic management.

Other port numbers listed in the choices serve different protocols. For instance, port 443 is used for HTTPS, which is the secure version of HTTP. Port 21 is used for FTP (File Transfer Protocol), and port 25 is associated with SMTP (Simple Mail Transfer Protocol) for email transmission. Understanding these distinctions is key for anyone working with network protocols and web traffic.