I'm having an incredibly tedious problem with port forwarding, and I have no idea how to solve it. Let's define my public IP as X and my kali's local one as Y. In my router's settings I've configured port forwarding for Y on port 4545, and up to this point everything works like a charm. After having made this configuration I try to check if my port is correctly forwarded on "Can you see me" and it does not recognize it at all, only and only if I execute nc -l -p 4545 on my kali machine the site says the port is actually forwarded, but after that nc shuts down and it's then again all closed. Apparently if i don't provide any data to that port it doesn't open at all thus is considered completely deactivated. I have no idea how to open it permanently without having the need to to subtle tasks such as activating it fakely with a netcat listener. I've tried enabling DMZ on Y, but it still does not work at all. I've tried to disable my router's firewall, and nothing. If you guys have any suggestions I'd really like to hear them because this is driving me nuts. Have a good day.