Subnet

Overview

a subnet

• Subnet is a sub of VPC network, which you can group resources based on security or operational needs. A range of IP addresses.

• 2 types of subnet (with its route table)

  • private subnet:
  • public subnet:

NAT Gateway

NAT Gateway

Route table

• The rule for traffic inside the VPC

• An important property of subnet. It contains set of rules, called routes. Routes are used to determine where network traffic, from your subnet or gateway, is directed.

• By default, it will contain rules of

  • local traffic.

  • 0.0.0.0/0 if a gateway is attached.

Trivia

• Each subnet must reside entirely within one AZ and cannot span zones.

• Every subnet that you create, automatically associated with the Main route table of the VPC.

Concepts

• Main route table: when you create a VPC, this table is automatically created. This control the routing of all the subnets that do not have a Custom route table associated with them.

  • Cannot be deleted.

  • Can be customized.