Network protocols work over different protocols like TCP and UDP. One of the most popular port numbers is TCP 443. The TCP 443 is dedicated to the HTTPS protocol which is the secure version of the HTTP protocol. The HTTP protocol is served via the TCP port 80. But the HTTP does not provide the security required for critical communication and HTTPS protocol is created which is assigned to the TCP port 443.
HTTPS Port 443 Usage
HTTPS is a web protocol that is used to transmit web pages in a secure and encrypted manner. The TCP port 443 is used for HTTPS protocol and is generally used with web browsers like Google Chrome, Mozilla Firefox, Opera, Microsoft Edge, etc. Just using the HTTPS Url like “https://www.wisetut.com” implicitly specifies to use the HTTPS protocol and adds the port number 443 to the end of the URL in a hidden way. For example “https://www.wisetut.com” is the same as “https://www.wisetut.com” unless a non-default port is used for the HTTPS protocol.
Check If TCP Port 443 Is Open?
Before connecting to the HTTPS via the TCP 443 we can check if the TCP port 443 is open on the remote server. there are different tools and ways to check this. The simplest and most practical way is using the browser with a specific HTTPS URL. Alternatively, we can specify the TCP port 443 in the URL like below.
Another way is using the telnet command to connect remote server TCP port number 443.
telnet www.wisetut.com 443
The Nmap is used to scan networks with different options. The remote server TCP 443 can be scanned with the Nmap tool and the result is listed whether open or closed.
nmap -p 443 www.wisetut.com
Port 443 Alternatives (TCP 8443 or TCP 80)
Almost all websites use TCP 443 as the HTTPS port. But some applications with web interfaces or some websites may use different ports instead of TCP 443. The most popular alternative ports are TCP 8443 and TCP 80. The TCP 8443 is used because of its similarity to the 443. Alternatively the TCP 80 is used reraly for HTTPS connections.