172.19.128.0/18
Private (RFC 1918) RFC 1918Class B — /18 prefix — 16,382 usable hosts
Network address — the base address of the block (172.19.128.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 172.19.191.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 16,382 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.192.0 is the dotted-decimal equivalent of /18. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 172.19.128.0/18 |
| Network Address | 172.19.128.0 |
| Broadcast Address | 172.19.191.255 |
| Subnet Mask | 255.255.192.0 |
| Wildcard Mask | 0.0.63.255 |
| Prefix Length | /18 |
| IP Address Class | Class B |
| Total IP Addresses | 16,384 |
| Usable Host Addresses | 16,382 |
| First Usable IP | 172.19.128.1 |
| Last Usable IP | 172.19.191.254 |
| Network (Hex) | 0xAC138000 |
| Broadcast (Hex) | 0xAC13BFFF |
| Governing RFC | RFC 1918 |
| Address Type | Private (RFC 1918) |
Binary Representation
The first 18 bits (1s in the mask) identify the network. The remaining 14 bits identify hosts within the network.
Split into Equal Subnets
Split 172.19.128.0/18 into 2 equal /19 subnets (8,190 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 172.19.128.0/19 | 172.19.128.0 | 172.19.128.1 | 172.19.159.254 | 172.19.159.255 | 8,190 |
| 2 | 172.19.160.0/19 | 172.19.160.0 | 172.19.160.1 | 172.19.191.254 | 172.19.191.255 | 8,190 |
Split 172.19.128.0/18 into 4 equal /20 subnets (4,094 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 172.19.128.0/20 | 172.19.128.0 | 172.19.128.1 | 172.19.143.254 | 172.19.143.255 | 4,094 |
| 2 | 172.19.144.0/20 | 172.19.144.0 | 172.19.144.1 | 172.19.159.254 | 172.19.159.255 | 4,094 |
| 3 | 172.19.160.0/20 | 172.19.160.0 | 172.19.160.1 | 172.19.175.254 | 172.19.175.255 | 4,094 |
| 4 | 172.19.176.0/20 | 172.19.176.0 | 172.19.176.1 | 172.19.191.254 | 172.19.191.255 | 4,094 |
Split 172.19.128.0/18 into 8 equal /21 subnets (2,046 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 172.19.128.0/21 | 172.19.128.0 | 172.19.128.1 | 172.19.135.254 | 172.19.135.255 | 2,046 |
| 2 | 172.19.136.0/21 | 172.19.136.0 | 172.19.136.1 | 172.19.143.254 | 172.19.143.255 | 2,046 |
| 3 | 172.19.144.0/21 | 172.19.144.0 | 172.19.144.1 | 172.19.151.254 | 172.19.151.255 | 2,046 |
| 4 | 172.19.152.0/21 | 172.19.152.0 | 172.19.152.1 | 172.19.159.254 | 172.19.159.255 | 2,046 |
| 5 | 172.19.160.0/21 | 172.19.160.0 | 172.19.160.1 | 172.19.167.254 | 172.19.167.255 | 2,046 |
| 6 | 172.19.168.0/21 | 172.19.168.0 | 172.19.168.1 | 172.19.175.254 | 172.19.175.255 | 2,046 |
| 7 | 172.19.176.0/21 | 172.19.176.0 | 172.19.176.1 | 172.19.183.254 | 172.19.183.255 | 2,046 |
| 8 | 172.19.184.0/21 | 172.19.184.0 | 172.19.184.1 | 172.19.191.254 | 172.19.191.255 | 2,046 |
Split 172.19.128.0/18 into 16 equal /22 subnets (1,022 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 172.19.128.0/22 | 172.19.128.0 | 172.19.128.1 | 172.19.131.254 | 172.19.131.255 | 1,022 |
| 2 | 172.19.132.0/22 | 172.19.132.0 | 172.19.132.1 | 172.19.135.254 | 172.19.135.255 | 1,022 |
| 3 | 172.19.136.0/22 | 172.19.136.0 | 172.19.136.1 | 172.19.139.254 | 172.19.139.255 | 1,022 |
| 4 | 172.19.140.0/22 | 172.19.140.0 | 172.19.140.1 | 172.19.143.254 | 172.19.143.255 | 1,022 |
| 5 | 172.19.144.0/22 | 172.19.144.0 | 172.19.144.1 | 172.19.147.254 | 172.19.147.255 | 1,022 |
| 6 | 172.19.148.0/22 | 172.19.148.0 | 172.19.148.1 | 172.19.151.254 | 172.19.151.255 | 1,022 |
| 7 | 172.19.152.0/22 | 172.19.152.0 | 172.19.152.1 | 172.19.155.254 | 172.19.155.255 | 1,022 |
| 8 | 172.19.156.0/22 | 172.19.156.0 | 172.19.156.1 | 172.19.159.254 | 172.19.159.255 | 1,022 |
| 9 | 172.19.160.0/22 | 172.19.160.0 | 172.19.160.1 | 172.19.163.254 | 172.19.163.255 | 1,022 |
| 10 | 172.19.164.0/22 | 172.19.164.0 | 172.19.164.1 | 172.19.167.254 | 172.19.167.255 | 1,022 |
| 11 | 172.19.168.0/22 | 172.19.168.0 | 172.19.168.1 | 172.19.171.254 | 172.19.171.255 | 1,022 |
| 12 | 172.19.172.0/22 | 172.19.172.0 | 172.19.172.1 | 172.19.175.254 | 172.19.175.255 | 1,022 |
| 13 | 172.19.176.0/22 | 172.19.176.0 | 172.19.176.1 | 172.19.179.254 | 172.19.179.255 | 1,022 |
| 14 | 172.19.180.0/22 | 172.19.180.0 | 172.19.180.1 | 172.19.183.254 | 172.19.183.255 | 1,022 |
| 15 | 172.19.184.0/22 | 172.19.184.0 | 172.19.184.1 | 172.19.187.254 | 172.19.187.255 | 1,022 |
| 16 | 172.19.188.0/22 | 172.19.188.0 | 172.19.188.1 | 172.19.191.254 | 172.19.191.255 | 1,022 |