Using unlimited IP addresses in AWS

IPv4 vs IPv6

IPv4 (Old)

• Total addresses: 4.3 Billion
• Problem: Running out of addresses
• In AWS: Has private and public ranges

IPv6 (New)

• Total addresses: 3.4 × 10³⁸ (practically unlimited)
• Problem: Never running out
• In AWS: All IPv6 addresses are public (no private range)
• Format: x.x.x.x.x.x.x.x (hexadecimal, 0000 to ffff)
• Example: 2001:db8::ff00:42:8329

IPv6 in VPC

Key Points

Cannot disable IPv4:

• IPv4 is always on in VPC
• Cannot turn off IPv4

Can enable IPv6:

• IPv6 is optional
• When enabled = Dual-stack mode (both IPv4 + IPv6 work together)

EC2 gets both:

• Private IPv4 address
• Public IPv6 address

Internet Gateway:

• Supports both IPv4 and IPv6
• Works with either protocol

Example Setup

EC2 Instance has:

Private IPv4: 10.0.0.5
Public IPv6: 2001:db8::ff00:42:8329