How to open a port in Oracle Cloud Instance?

open-a-port-in-oracle-cloud-instance.sh

# +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
# IMPORTANT
# Make sure you already create an ingress rule for the port that you want to open in Oracle Cloud virtual firewall aka
# "Security Lists". This tutorial might be useful for you:
# ---> https://youtu.be/1AIXULHjabQ
# +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

# SSH into the instance
$ ssh <username>@<ip_address>

# Install
$ sudo apt-get install -y firewalld

# Open the port (e.g. port 80)
$ sudo firewall-cmd --zone=public --permanent --add-port=80/tcp

# Reload
$ sudo firewall-cmd --reload

# Verify using another machine (e.g. local/dev machine)
$ nc -zv <ip_address> 80
Connection to <ip_address> port 80 [tcp/http] succeeded!