You have an environment that consists of a public subnet using Amazon VPC and 3
instances that are running in this subnet. These three instances can successfully
communicate with other hosts on the Internet. You launch a fourth instance in the same
subnet, using the same AMI and security group configuration you used for the others, but find
that this instance cannot be accessed from the internet.
What should you do to enable Internet access?
Deploy a NAT instance into the public subnet.
Assign an Elastic IP address to the fourth instance.
Configure a publically routable IP Address in the host OS of the fourth instance.
Modify the routing table for the public subnet.
You launched your instance into a public subnet – a subnet that has a route to an Internet
gateway. However, the instance in your subnet also needs a public IP address to be able to
communicate with the Internet. By default, an instance in a nondefault VPC is not assigned a
public IP address. In this step, you’ll allocate an Elastic IP address to your account, and then
associate it with your instance.