AWS VPC Interview Guide: Top 10 Questions with Answers

Question 1: What is AWS VPC?
Answer: AWS VPC is a logically isolated virtual network within the AWS cloud. It allows you to define and control your virtual network environment, including IP addressing, subnets, routing tables, and security settings.

Question 2: What are the benefits of using VPC?
Answer: Some benefits of using VPC include:

1. Enhanced security by isolating resources within a private network.

2. Customizable network configuration.

3. Ability to connect on-premises infrastructure to the cloud using VPN or Direct Connect.

4. Scalability and flexibility to add or remove resources as needed.

5. Fine-grained control over network traffic and security.

Question 3: What is a subnet in VPC?
Answer: A subnet is a range of IP addresses in your VPC. It is a subdivision of the IP address range of your VPC and allows you to segment your network into smaller networks. Each subnet must be associated with a route table and can be public or private.

Question 4: How does VPC peering work?
Answer: VPC peering allows you to connect two VPCs together using private IP addresses. It enables resources in different VPCs to communicate with each other as if they were on the same network.

Question 5: What is an Internet Gateway (IGW)?
Answer: An Internet Gateway is a horizontally scalable, redundant, and highly available gateway that allows communication between your VPC and the internet. It enables instances within a VPC to have outbound internet access and allows inbound traffic initiated from the internet.

Question 6: What is Network Access Control List (NACL)?
Answer: NACL is a stateless firewall that controls traffic at the subnet level. It acts as a barrier to control both inbound and outbound traffic at the protocol and subnet level. NACLs are associated with subnets and evaluate rules in a sequential order.

Question 7: What is a Security Group?
Answer: A Security Group acts as a virtual firewall for your instances in a VPC. It controls inbound and outbound traffic at the instance level. Security Groups are stateful, meaning if you allow an inbound request, the corresponding outbound response is automatically allowed.

Question 8: How can you connect your VPC to your corporate data center?
Answer: You can connect your VPC to your corporate data center using either VPN (Virtual Private Network) or AWS Direct Connect. VPN provides an encrypted connection over the internet, while Direct Connect establishes a dedicated network connection.

Question 9: What is a NAT Gateway?
Answer: A NAT Gateway is a managed AWS service that allows instances within a private subnet to access the internet. It enables outbound internet traffic but doesn't allow inbound traffic initiated from the internet.

Question 10: How do you control traffic between subnets in VPC?
Answer: Traffic between subnets in VPC can be controlled using route tables, Network Access Control Lists (NACLs), and Security Groups. Route tables define the traffic's path between subnets, NACLs filter traffic at the subnet level, and Security Groups control traffic at the instance level.

Remember that these are just sample questions, and it's important to thoroughly understand the concepts behind them to excel in an interview. Good luck!