sudo chown Username /media/usbdisk
Я также добавил бы-R, таким образом, он воздействует на все файлы и каталоги.
After PREROUTING local packets go to the local filter where they get dropped (your case 2).
So you just need to allow incoming traffic to those ports in iptables:
iptables -A INPUT -p tcp -m tcp --dport 8080 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 3000 -j ACCEPT
Since you are redirecting http(s) traffic from 80/443 to 8080/3000 is like the latter ports are open and exposed to the Internet anyways, so there's no difference from the outside wrorld and there are no further security implications.