Secure Sockets Layer (SSL) is the technology responsible for data authentication and encryption for internet connections. It encrypts data being sent over the internet between two systems (commonly between a server and a client) so that it remains private. Because data can be sent with or without the use of SSL, one way to indicate a secure connection is by the port number. By default, HTTPS connections use TCP port 443 . HTTP, the unsecure protocol, uses port 80.
Data transferred across such connections are highly resistant to eavesdropping and interception. Moreover, the identity of the remotely connected server can be verified with significant confidence. Web servers offering to accept and establish secure connections listen on this port for connections from web browsers desiring strong communication security. Once established, web browsers inform their users of these secured connections by displaying an icon — a padlock, an unbroken key, etc. — in the status region of their window.
The default port for https is 443, but you can however run SSL over a different port than 443 by simply adding a binding for https and a different port. What you have to keep in mind is that by not using a standard port you may have problems with the client's firewall . For example it is common practice that in corporate networks only a small set of ports is open (e.g., 80 and 443), and client connections to non-standard ports will be rejected.
TCP port 443 is the default port used by HTTPS. If this port is blocked on any server or device from your computer to a given destination, such as www.Microsoft.com, your connection to any https site will fail and your browser will return an error message like "Secure Connection Failed" or "Page Cannot be Displayed" . However, the two most common locations for this failure are at your workstation or router. Moreover, if you can access the html page at your root domain (say https://midomain.com/), but pages in a directory like https://midomain.com/ give you a 404 Not Found error.
NEXT.....This site can't be reached Error