Oracle Instance only reachable via 22 , no other ports are reachable solution

Recently, when I create a new instance in OCI, i can only reach it via 22.

It is caused by iptables now are install and enabled on default .

YOu can choose either remove iptables once for all , or add rules each time when you openning new ports.

I choose to remove it, else what is the point of NSGs at all.

To add ports:

# to add ports
sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 80 -j ACCEPT

sudo netfilter-persistent save

To uninstall iptables:

sudo apt remove iptables
sudo reboot # remember to reboot...