203.0.113.128/28
Public RFC 5737Class C — /28 prefix — 14 usable hosts
Network address — the base address of the block (203.0.113.128). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 203.0.113.143 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 14 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.255.240 is the dotted-decimal equivalent of /28. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 203.0.113.128/28 |
| Network Address | 203.0.113.128 |
| Broadcast Address | 203.0.113.143 |
| Subnet Mask | 255.255.255.240 |
| Wildcard Mask | 0.0.0.15 |
| Prefix Length | /28 |
| IP Address Class | Class C |
| Total IP Addresses | 16 |
| Usable Host Addresses | 14 |
| First Usable IP | 203.0.113.129 |
| Last Usable IP | 203.0.113.142 |
| Network (Hex) | 0xCB007180 |
| Broadcast (Hex) | 0xCB00718F |
| Governing RFC | RFC 5737 |
| Address Type | Public / Globally Routable |
Binary Representation
The first 28 bits (1s in the mask) identify the network. The remaining 4 bits identify hosts within the network.
Subnet Breakdown — splitting into /29
This /28 block can be divided into 2 /29 subnets.
| CIDR | Network | Broadcast | First Usable | Last Usable | Hosts |
|---|---|---|---|---|---|
| 203.0.113.128/29 | 203.0.113.128 | 203.0.113.135 | 203.0.113.129 | 203.0.113.134 | 6 |
| 203.0.113.136/29 | 203.0.113.136 | 203.0.113.143 | 203.0.113.137 | 203.0.113.142 | 6 |