Aug 25, 2017

All such secure transfers are done using port 443, the standard port for HTTPS traffic. However, HTTPS port 443 also supports sites to be available over HTTP connections. If the site uses HTTPS but is unavailable over port 443 for any reason, port 80 will step in to load the HTTPS-enabled website. TCP 443 - Port Protocol Information and Warning! Side note: TCP port 443 uses the Transmission Control Protocol. TCP is one of the main protocols in TCP/IP networks. Whereas the IP protocol deals only with packets, TCP enables two hosts to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered on port 443 in the Difference Between HTTPS Port 443 and Port 8443 Mar 01, 2018

All such secure transfers are done using port 443, the standard port for HTTPS traffic. However, HTTPS port 443 also supports sites to be available over HTTP connections. If the site uses HTTPS but is unavailable over port 443 for any reason, port 80 will step in to load the HTTPS-enabled website.

Newest 'port-443' Questions - Server Fault

Nov 15, 2015

HTTPS with port 443 - Server Fault