172.31.0.128/25
Private (RFC 1918) RFC 1918Class B — /25 prefix — 126 usable hosts
Network address — the base address of the block (172.31.0.128). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 172.31.0.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 126 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.255.128 is the dotted-decimal equivalent of /25. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 172.31.0.128/25 |
| Network Address | 172.31.0.128 |
| Broadcast Address | 172.31.0.255 |
| Subnet Mask | 255.255.255.128 |
| Wildcard Mask | 0.0.0.127 |
| Prefix Length | /25 |
| IP Address Class | Class B |
| Total IP Addresses | 128 |
| Usable Host Addresses | 126 |
| First Usable IP | 172.31.0.129 |
| Last Usable IP | 172.31.0.254 |
| Network (Hex) | 0xAC1F0080 |
| Broadcast (Hex) | 0xAC1F00FF |
| Governing RFC | RFC 1918 |
| Address Type | Private (RFC 1918) |
Binary Representation
The first 25 bits (1s in the mask) identify the network. The remaining 7 bits identify hosts within the network.
Subnet Breakdown — splitting into /26
This /25 block can be divided into 2 /26 subnets.
| CIDR | Network | Broadcast | First Usable | Last Usable | Hosts |
|---|---|---|---|---|---|
| 172.31.0.128/26 | 172.31.0.128 | 172.31.0.191 | 172.31.0.129 | 172.31.0.190 | 62 |
| 172.31.0.192/26 | 172.31.0.192 | 172.31.0.255 | 172.31.0.193 | 172.31.0.254 | 62 |
IP Address Sample
Showing first 16 of 128 total IPs.