AWS VPC Interview Questions & Answers (2025)

You can use any IPv4 address range, including RFC 1918 or publicly routable IP ranges, for the primary CIDR block. For the secondary CIDR blocks, certain restrictions apply. Publicly routable IP blocks are only reachable via the Virtual Private Gateway and cannot be accessed over the Internet through the Internet gateway. AWS does not advertise customer-owned IP address blocks to the Internet. You can allocate an Amazon-provided IPv6 CIDR block to a VPC by calling the relevant API or via the AWS Management Console.

AWS VPC better known as Amazon Virtual Private Cloud lets you furnish a logically left out department of the Amazon Web Services. Here you can launch Amazon Web Services Resources in a virtual network that is defined by you. You will have absolute control over your virtual networking environment along with the privilege of choosing your own IP address range, network gateways, the configuration of route tables and the creation of subnets. You can also establish a hardware VPN connection between your corporate data center as well as your VPC and influence the AWS cloud as an extension of your corporate data center.

It is good news that Amazon VPC enables the creation of an Internet gateway. This allows Amazon EC2 occurrences in the VPC to access the Internet directly. There are numerous connectivity options for my VPC.  You can connect your Virtual Private Cloud to the following:

• Your corporate data center with the help of a Hardware Virtual Private Network connection
• The Internet through an internet gateway
• The Internet as well as your corporate data center, together. You can do this by using both, the virtual private gateway and the Internet gateway.
• Other VPCs through Virtual Private Cloud Peering condition
• Other Amazon Web Services

• VPC- a logically secluded virtual network in the Amazon Web Services cloud. You only need to define a Virtual Private Cloud’s IP address space from the range that you select
• Internet Gateway- Internet Gateway is the Amazon VPC’s side of a connection to the public internet
• Subnet- Subnet is a part of cloud’s IP address space from the range that you select
• NAT Gateway- A highly available and managed NAT service for your resources in a private subnet to use the internet
• Virtual Private Gateway- This is the Amazon VPC’s side of a VPN connection
• Customer Gateway- It is the user’s side of a VPN connection
• Router- Routers interconnect subnets and the direct traffic between Virtual Private Gateways, Internet Gateways, NAT gateways as well as subnets.

• Create a Virtual Private Cloud
• Then create Subnets
• Further create an Internet Gateway
• Attach this new Gateway to your VPC
• Create a new Route Table
• Add the gateway as a route to the new route table
• Add a subnet to the route table’s subnet association
• Create a web server for public subnet and a database server for the private subnet
• Create a new security group for the NAT
• Add HTTP and HTTPS inbound rules that let in traffic from the private subnets IP
• Create a NAT for public subnet
• Create an elastic IP
• Associate this IP to the NAT
• Disable destination/source checks for the NAT
•  Add NAT to the initial VPC route table as a route.

In case of Stateless Filtering, it doesn’t matter whether a new request is generated or an automatic reply is sent to a request, the filter only seeks the origin or destination IP address & port.

When Amazon EC2 instance is launched you must specify the subnet in which to launch the instance. This instance will be then launched in the availability zone that is associated with the given subnet.

You can very well use your existing AMIs in Amazon VPC that is registered within the same region as your VPC.

Secondly, without creating a VPC or launching the instances, the user can still avail several features such as different IP address, altering the security group membership, egress filtering of the security group and several network interfaces.

You can use any IPv4 address range, including RFC 1918 or publicly routable IP ranges, for the primary CIDR block IP addresses range in a VPC.