I’m happy to provide you with the top 10 AWS VPC interview questions and answers. These questions will give you an understanding of what you might be asked in an interview for a role that involves working with AWS VPCs.
- What is a VPC in AWS?
Answer: A Virtual Private Cloud (VPC) is a virtual network in AWS that provides a logically isolated environment for your resources. You can define your IP address range, create subnets, configure route tables, and set up network gateways for better security and control over your resources.
- What are the components of a VPC?
Answer: The main components of a VPC include:
- Subnets
- Route Tables
- Internet Gateways
- NAT Gateways
- Network ACLs
- Security Groups
- VPC Peering
- VPC Endpoints
- VPN Connections
- What is the difference between a public and private subnet in a VPC?
Answer: A public subnet is a subnet that has a route to the Internet through an Internet Gateway. Instances within the public subnet can have a public IP address and can be accessed from the Internet. A private subnet, on the other hand, does not have a direct route to the Internet and cannot be accessed directly from the Internet. Instances within a private subnet can communicate with the Internet through a NAT Gateway.
- How do you secure resources within a VPC?
Answer: To secure resources within a VPC, you can use Security Groups and Network Access Control Lists (NACLs). Security Groups act as a virtual firewall for instances, controlling inbound and outbound traffic at the instance level. NACLs are stateless and provide an additional layer of security, controlling inbound and outbound traffic at the subnet level.
- What is VPC peering?
Answer: VPC peering is a networking connection between two VPCs that allows you to route traffic between them using private IPv4 addresses or IPv6 addresses. This connection can be established between VPCs in the same AWS account or across different accounts, and even across different regions.
- What is the difference between a NAT Gateway and a NAT Instance?
Answer: A NAT Gateway is a managed AWS service that provides source network address translation (SNAT) to instances in a private subnet, allowing them to access the Internet but preventing them from receiving inbound traffic initiated by external sources. A NAT Instance is an EC2 instance configured to perform the same function. NAT Gateways offer higher availability, better bandwidth, and maintenance-free operation compared to NAT Instances.
- What are VPC Endpoints?
Answer: VPC Endpoints allow you to privately connect your VPC to supported AWS services and VPC endpoint services, without requiring an Internet Gateway, NAT device, VPN connection, or AWS Direct Connect. There are two types of VPC Endpoints: Interface Endpoints and Gateway Endpoints.
- Can you have multiple Internet Gateways for a single VPC?
Answer: No, you can only have one Internet Gateway attached to a VPC at any given time. An Internet Gateway allows communication between instances in your VPC and the Internet and is used to provide a route for traffic from the VPC to the Internet.
- What is the maximum number of VPCs you can have per region in an AWS account?
Answer: By default, the maximum number of VPCs allowed per region in an AWS account is 5. However, you can request a limit increase from AWS if needed.
- How can you connect your on-premises data center to an AWS VPC?
Answer: To connect your on-premises data center to an AWS VPC, you can use either AWS Direct Connect or a Virtual Private Network (VPN) connection.
AWS Direct Connect establishes a dedicated network connection between your on-premises network and your AWS VPC, providing more consistent network performance and higher bandwidth. This is a suitable option for organizations with high data transfer requirements.
A VPN connection, on the other hand, establishes a secure and encrypted connection between your on-premises network and your AWS VPC over the public Internet. This is a cost-effective option for organizations that do not require the high performance and bandwidth provided by AWS Direct Connect.
Both options involve configuring a virtual private gateway in your VPC and a customer gateway in your on-premises network.
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