Public vs private subnets in AWS - Quick Revision & Key Differences

Recall & Review

beginner

What is a public subnet in AWS?

A public subnet is a subnet that has a route to the internet through an internet gateway. Resources in this subnet can communicate directly with the internet.

beginner

What is a private subnet in AWS?

A private subnet is a subnet that does not have a direct route to the internet. Resources here cannot be accessed directly from the internet but can access the internet through a NAT device.

intermediate

Why use private subnets instead of public subnets?

Private subnets increase security by keeping sensitive resources away from direct internet access, reducing exposure to attacks.

intermediate

How does a NAT gateway help private subnets?

A NAT gateway allows resources in private subnets to access the internet for updates or downloads without exposing them to inbound internet traffic.

beginner

What AWS component enables internet access for a public subnet?

An Internet Gateway attached to the VPC enables internet access for public subnets by routing traffic between the subnet and the internet.

Which AWS subnet type has a direct route to the internet?

A VPN subnet

B Private subnet

C Isolated subnet

D Public subnet

Public subnets have a route to the internet via an internet gateway.

What device allows private subnet resources to access the internet safely?

A NAT Gateway

B Load Balancer

C VPN Gateway

D Internet Gateway

NAT Gateway enables outbound internet access for private subnet resources without exposing them to inbound internet traffic.

Which subnet type is best for hosting a public web server?

A Private subnet

B Isolated subnet

C Public subnet

D Backend subnet

Public subnets allow direct internet access, suitable for public web servers.

What is a key security benefit of private subnets?

A No inbound internet traffic

B No internet access at all

C Direct internet access

D Automatic backups

Private subnets block inbound internet traffic, reducing exposure to attacks.

Which AWS component must be attached to a VPC to enable public subnet internet access?

A NAT Gateway

B Internet Gateway

C Virtual Private Gateway

D Transit Gateway

Internet Gateway connects the VPC to the internet, enabling public subnet access.

Explain the difference between a public subnet and a private subnet in AWS.

Think about how resources connect to the internet and security.

Describe how a NAT gateway works with private subnets to allow internet access.

Focus on the path outbound traffic takes from private subnet.