Detailed information about IPv4 /0 subnets
The /0 CIDR represents the entire IPv4 address space. It's not typically used for regular networks but for default routes.
| CIDR Notation | /0 |
| Subnet Mask | 0.0.0.0 |
| Binary Subnet Mask | 00000000 00000000 00000000 00000000 |
| Total Addresses | 4,294,967,296 |
| Usable Hosts (Standard) | 4,294,967,294 |
| AWS Usable IPs | 4,294,967,289 |
| Azure Usable IPs | 4,294,967,289 |
| GCP Usable IPs | 4,294,967,290 |
A CIDR /0 subnet has 4,294,967,294 usable IP addresses for hosts. This is a relatively large subnet that can be further divided into smaller subnets if needed.
Organizations typically use subnets of this size for large-scale deployments or when planning for future growth.
Cloud providers reserve some IP addresses in each subnet for internal use, resulting in fewer usable IPs:
When planning your cloud infrastructure, consider these reserved addresses to accurately size your subnets.