AWS Cloud Series

Concise AWS VPC reference Guide

AWS | Cloud | Network

Arun Kumar Singh
6 min readNov 18, 2022
Photo by Taylor Vick on Unsplash


This post talks about few AWS Cloud VPC concepts in brief. I have not covered anything new in this post, but tried to collect important concepts that can give good idea of overall VPC specific AWS services. This post can also give good recap to those who are thinking of taking the AWS Certification Exams.

Let’s dive in ….


  • Own virtual network inside AWS, scattered through 4 virtual walls (region, AZ, IPv4, IPV6 CIDR block).
  • Spans through all AZs in an entire region
  • Can connect to other networks using VPN or using Direct Connect to physical networks (ex On Premises)


  • You need to create a subnet to use a VPC
  • Limited to a single AZ, provides routing boundaries
  • There is no concept of public or private subnet logically. A subnet becomes public when it has a default route to internet using Internet Gateway. All resources have public IP addresses assigned by default or not? Otherwise all subnets are private by default.
  • Public IP to the resources can be allocated by default or can be allocated explicitly.

By default no traffic can leave VPC. To make traffic go out or come in you need gateways ! There are many options for your need.
- Internet Gateway
- NAT Gateway
- AWS Transit Gateway
- VPC Endpoint
Don’t worry we will cover everything.

Routing in VPC

Route Table is core component of routing in VPC. Routes are set of rules that are used to determine where network traffic will flow.

  • Route tables contains rules for packets to move around
  • VPC has default route table
  • There is a route table per VPC but you can have route table at subnet level as well.

Internet Gateway



Arun Kumar Singh

In quest of understanding How Systems Work !