I know this is really basic stuff but I need to take a note here because I always forget this syntax.
stunnel3 -d 8443 -r 192.168.1.10:443 -c
To chat with a, let’s say, SSL enabled web server through a connection to localhost (-d parameter defaults to localhost if no IP is selected).
Originally, stunnel3 was intended to wrap the connection for not SSL capable services, so in order to use it for a more pentest suited perspective we must explicitly say that we are in “client” mode. Therefore the -c modifier.