What action should be taken if a new EC2 instance in a public subnet cannot access the internet?

Adding an Elastic IP address to the new EC2 instance is a valid solution for enabling internet access because an Elastic IP is a static public IP address that can be associated with an EC2 instance. When an instance is assigned an Elastic IP, it can communicate with the internet, as it provides a consistent, reachable address for external traffic.

However, it's important to note that simply adding an Elastic IP address may not necessarily resolve the internet connectivity issue if the other necessary configurations are not in place. For example, the instance also needs to have the appropriate routing configured to direct outbound traffic through the internet gateway, and the security groups need to allow the necessary inbound and outbound traffic.

In terms of other actions, enabling public IP addressing in the subnet is a preventative measure taken at the subnet level, and this affects instances launched in that subnet going forward. Adjusting security group settings can control access to and from the instance, ensuring that the required ports are open for communication, which is crucial for connectivity. Changing the instance type typically pertains to changing its resource allocation (like CPU and memory) and does not influence network access on its own.

Thus, while associating an Elastic IP may often facilitate seeing the instance from the internet, the overall networking configuration also