What is an IP Address in EC2

• Every EC2 instance needs an IP address to communicate within AWS or with the internet.
• AWS provides two types of IPs:
  • Private IP – for internal communication within the same VPC.
  • Public IP – for external communication (internet access).

Private IP

Definition

• A private IP is assigned from the subnet’s private range within your VPC.
• Used for communication between resources inside the same VPC (e.g., EC2 to RDS).
• Not accessible from the internet.

Key Points

• Assigned automatically when an instance is launched.
• Remains the same even after stop/start (unless manually changed).
• Each instance has one primary private IP and can have multiple secondary private IPs (for ENI-based setups).

Example

• VPC Subnet: 10.0.1.0/24
• EC2 Instance Private IP: 10.0.1.10
• This instance can communicate with others in the same VPC but not with the internet directly.

Public IP

Definition