4.01. Private and Public AWS Services

What are the two main categories of AWS services?

Public services and private services

What determines whether an AWS service is public or private?

Its network accessibility — whether it uses public endpoints or is deployed inside a VPC

Is S3 a public or private service?

Public — it uses public endpoints accessible via the internet

What is an example of a private AWS service?

EC2 instances inside a VPC

Does “public service” mean unrestricted access to anyone?

No — public/private in this context refers to networking, not permissions

Can public services like S3 still be restricted?

Yes — via IAM policies and permissions

What are the three core network zones in AWS?

Public Internet, AWS Public Zone, and AWS Private Zone (VPC)

What is the AWS Public Zone?

A network area between the public internet and private VPCs where AWS public services like S3 operate

How can a VPC communicate with the public internet?

By attaching an Internet Gateway and assigning public IPs to resources

Does traffic to public AWS services (like S3) always go over the public internet?

Not necessarily — if coming from within AWS (e.g., a VPC), traffic can go directly via the AWS Public Zone without touching the internet

What does it mean to assign a public IP to a private resource like EC2?

It projects the instance into the public zone for bi-directional internet communication

Can VPCs communicate with each other by default?

No — VPCs are isolated by default. Connectivity must be explicitly configured (e.g., VPC peering, Transit Gateway)

How do private networks (like on-premises) connect to AWS VPCs securely?

Through VPNs or AWS Direct Connect

Why is it important to distinguish between AWS public and private zones?

Because it affects security, connectivity, and architecture decisions, especially in complex deployments

What provides a clearer model than just “internet vs. private” zones?

A three-zone model: Public Internet, AWS Public Zone, AWS Private Zone

[Diagram] Architecture of Public Internet Zone, AWS Public Zone and AWS Private Zone.