VPC - PART 3

What is the function of a Security Group in AWS?

• Controls inbound and outbound traffic at the instance level

• Encrypts all VPC traffic

• Acts as a firewall for Route Tables

• Manages IAM permissions

Answer explanation

A Security Group in AWS acts as a virtual firewall, controlling inbound and outbound traffic at the instance level. It allows you to specify which traffic is permitted to reach your instances.

How do Security Groups differ from Network ACLs?

• Security Groups are stateless, Network ACLs are stateful

• Security Groups operate at the subnet level, Network ACLs at the instance level

• Security Groups are stateful, Network ACLs are stateless

• Security Groups control inbound traffic only, Network ACLs control outbound traffic only

Answer explanation

Security Groups are stateful, meaning they track the state of connections, while Network ACLs are stateless, treating each request independently. This fundamental difference affects how traffic is managed in a network.

What is the significance of using both Network ACLs and Security Groups?

• It simplifies network configuration

• It provides layered security

• It reduces the number of subnets

• It eliminates the need for ENIs

Answer explanation

Using both Network ACLs and Security Groups provides layered security by allowing multiple levels of filtering for inbound and outbound traffic, enhancing the overall security posture of the network.

Which component is required to allow an EC2 instance in a private subnet to access the internet?

• NAT Gateway

• Security Group

• Network ACL

• Elastic Load Balancer

Answer explanation

A NAT Gateway is required for an EC2 instance in a private subnet to access the internet. It allows outbound internet traffic while keeping the instance secure from direct inbound traffic.

What happens if you remove an Internet Gateway from a VPC?

• All public internet access is lost

• The VPC is deleted

• NAT Gateways stop working

• Security Groups are disabled

Answer explanation

Removing an Internet Gateway from a VPC results in the loss of all public internet access. This means that instances in the VPC can no longer communicate with the internet, affecting any services relying on such connectivity.

What is the function of Elastic IPs?

• To provide dynamic IP addresses

• To provide fixed, static IP addresses

• To assign private IP addresses

• To create subnets

Answer explanation

Elastic IPs are designed to provide fixed, static IP addresses that can be associated with your cloud resources. This allows for consistent access to your services, even if the underlying infrastructure changes.

How can you ensure high availability in a VPC?

• Deploying resources across multiple Availability Zones

• Using a single subnet

• Removing NAT Gateways

• Using only private IPs

Answer explanation

Deploying resources across multiple Availability Zones ensures high availability by distributing workloads. If one zone fails, resources in another zone can continue to operate, minimizing downtime.

What is a common use case for a VPC?

• Hosting secure web applications

• Running AWS Lambda without permissions

• Storing static websites without networking

• Managing billing reports

Answer explanation

A common use case for a VPC is hosting secure web applications, as it allows for isolated networking, enhanced security, and control over resources, making it ideal for sensitive applications.

A hybrid cloud setup using AWS VPC allows:

• Connecting an on-premises network to AWS

• Running EC2 instances without networking

• Using only IPv6 addresses

• Encrypting S3 storage

Answer explanation

A hybrid cloud setup using AWS VPC enables connecting an on-premises network to AWS, allowing for seamless integration and resource sharing. The other options do not accurately describe the capabilities of a hybrid cloud setup.

A public IP address in AWS is:

• An IP address reachable from the internet

• An internal address used for communication within the VPC

• An IPv6-only address

• An alias for an Elastic IP

Answer explanation

A public IP address in AWS is an IP address reachable from the internet, allowing external access to resources. The other options describe internal addresses, IPv6 specifics, or Elastic IPs, which are not the definition of a public IP.