Your VPC CIDR block determines available IPs and affects connectivity with other networks. Poor choices create expensive problems.
Size considerations:
- Too small: you run out of addresses
- Too large: you waste space across regions
- Most VPCs use or
Overlap prevention:
- VPCs cannot peer if CIDRs overlap
- Avoid overlaps with on-premises networks
Recommendations:
- Use RFC private ranges
- Create a CIDR allocation plan across environments
- Reserve blocks for future expansion