172.16.0.0/15
Private (RFC 1918) RFC 1918Class B — /15 prefix — 131,070 usable hosts
Network address — the base address of the block (172.16.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 172.17.255.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 131,070 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.254.0.0 is the dotted-decimal equivalent of /15. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 172.16.0.0/15 |
| Network Address | 172.16.0.0 |
| Broadcast Address | 172.17.255.255 |
| Subnet Mask | 255.254.0.0 |
| Wildcard Mask | 0.1.255.255 |
| Prefix Length | /15 |
| IP Address Class | Class B |
| Total IP Addresses | 131,072 |
| Usable Host Addresses | 131,070 |
| First Usable IP | 172.16.0.1 |
| Last Usable IP | 172.17.255.254 |
| Network (Hex) | 0xAC100000 |
| Broadcast (Hex) | 0xAC11FFFF |
| Governing RFC | RFC 1918 |
| Address Type | Private (RFC 1918) |
Binary Representation
The first 15 bits (1s in the mask) identify the network. The remaining 17 bits identify hosts within the network.
Subnet Breakdown — splitting into /16
This /15 block can be divided into 2 /16 subnets.
| CIDR | Network | Broadcast | First Usable | Last Usable | Hosts |
|---|---|---|---|---|---|
| 172.16.0.0/16 | 172.16.0.0 | 172.16.255.255 | 172.16.0.1 | 172.16.255.254 | 65,534 |
| 172.17.0.0/16 | 172.17.0.0 | 172.17.255.255 | 172.17.0.1 | 172.17.255.254 | 65,534 |