Recently my friend asked me whether his network is secure because he is setting up a game server on port XXX.
I opened up Nmap on my linux machine and found port 443 opened. I tried to access
https://xxx.xxx.xxx.xxx:443
It redirected me to his ISP's website. That means that his router responded to my web request.
How would hackers use this imformation to DDOS his router or gain unauthorised access to his network?