Introduction to VPC
Explore the fundamentals of AWS Virtual Private Cloud including CIDR notation, private and public IP addressing, VPC peering limitations, and the use of VPC endpoints. Learn how to interpret VPC flow logs and understand the features of default and custom VPCs. This lesson prepares you to configure and manage AWS networking effectively.
Virtual Private Cloud
As the name suggests, Virtual Private Cloud (VPC) is a private, virtual network in AWS dedicated to an account. VPC is logically isolated from all other VPCs (in the same or different accounts) in the AWS network.
- VPC is a region-specific service (i.e., a VPC is limited to one AWS Region).
- A VPC spans all AZs in its region.
- Each VPC can have its own network configuration.
CIDRs and IPs
Before we dive into AWS networking and VPC, it’s crucial to understand Classless Inter-Domain Routing (CIDR), a way to represent IP address ranges. CIDR consists of 32 bits and is usually represented as four dots (.) separating numbers (octets), followed by a suffix. The suffix, also called a subnet mask, defines the total number of bits in the address.
Let’s look at an example. The following illustration shows four numbers, their binary representations, and a range of their bits.
The subnet mask in the CIDR range specifies the number of fixed bits in an IP address range. CIDR range 182.228.169.61/32 implies that all 32 bits in the IP address range are fixed, which means that CIDR 182.228.169.61/32 specifies one IP address, 182.228.169.61.
Similarly, CIDR range 182.228.169.61/16 implies that the first 16 bits in the IP address range are fixed. This means that CIDR 182.228.169.61/16 specifies an IP address range from 182.228.0.0 to ...