What type of IP address allows instances to communicate internally within a private network?

Instances that require communication internally within a private network utilize private IP addresses. These addresses are not routable over the public internet, which enhances security by ensuring that internal communication remains within the boundaries of the private network.

Private IP addresses are used within a Virtual Private Cloud (VPC) to enable resources, such as EC2 instances, to communicate with one another without exposing them to external networks. Each instance within a VPC can have a private IP address assigned from the private address ranges defined by RFC 1918, which include:

• 10.0.0.0 to 10.255.255.255

• 172.16.0.0 to 172.31.255.255

• 192.168.0.0 to 192.168.255.255

Using private IP addresses is essential when building secure, cost-effective solutions, particularly when instances are meant to share data or services without the risk of exposure to the public internet.

While Elastic IP addresses are designed to allow instances to interact with the internet, Public IP addresses can be used for communication over the internet at large. Static IP is a term often used to describe IP addresses that do not change but is not a specific AWS service or feature