What protocol is associated with port 443?

Port 443 is associated with HTTPS, which stands for Hypertext Transfer Protocol Secure. This protocol is an extension of HTTP and is used for secure communication over a computer network. HTTPS incorporates Transport Layer Security (TLS) or its predecessor, Secure Sockets Layer (SSL), to provide authentication, data integrity, and encryption between a client (such as a web browser) and a server.

The primary reason HTTPS uses port 443 instead of the standard port 80 used by HTTP is due to the need for security in communication. The encrypted nature of HTTPS ensures that data transmitted between users and websites remains confidential and protected from eavesdropping and tampering, which is vital for online transactions, data exchange, and privacy-critical applications.

By contrast, HTTP, which operates on port 80, does not provide the same level of security and is thus less suitable for sensitive transactions. Protocols like FTP (File Transfer Protocol) and SMTP (Simple Mail Transfer Protocol) operate on entirely different ports and serve different purposes, with FTP being used for transferring files and SMTP being used for sending emails. This distinction further underscores why HTTPS is specifically associated with port 443 for secure web communication.