This is a golang-based Cobra CLI utility to calculate subnets when given an IP address and a subnet mask in CIDR notation. It will return the host address range, network address, broadcast address, subnet mask, maximum number of subnets, and maximum number of hosts. It works as expected with IPv4, however IPv6 handling is questionable at best.
subnetCalc <ip address>/<subnet mask>
subnetCalc 10.12.34.56/19
Network: 10.12.32.0/19
Host Address Range: 10.12.32.1 - 10.12.63.254
Broadcast Address: 10.12.63.255
Subnet Mask: 255.255.224.0
Maximum Subnets: 2,048
Maximum Hosts: 8,190
subnetCalc 192.168.10.0/25 --subnet_size 27
Network: 192.168.10.0/25
Host Address Range: 192.168.10.1 - 192.168.10.126
Broadcast Address: 192.168.10.127
Subnet Mask: 255.255.255.128
Maximum Subnets: 2
Maximum Hosts: 126
192.168.10.0/25 contains 4 /27 subnets:
╭───┬──────────────────┬───────────────┬────────────────┬────────────────┬───────╮
│ # │ SUBNET │ FIRST IP │ LAST IP │ BROADCAST │ HOSTS │
├───┼──────────────────┼───────────────┼────────────────┼────────────────┼───────┤
│ 1 │ 192.168.10.0/27 │ 192.168.10.1 │ 192.168.10.30 │ 192.168.10.31 │ 30 │
│ 2 │ 192.168.10.32/27 │ 192.168.10.33 │ 192.168.10.62 │ 192.168.10.63 │ 30 │
│ 3 │ 192.168.10.64/27 │ 192.168.10.65 │ 192.168.10.94 │ 192.168.10.95 │ 30 │
│ 4 │ 192.168.10.96/27 │ 192.168.10.97 │ 192.168.10.126 │ 192.168.10.127 │ 30 │
╰───┴──────────────────┴───────────────┴────────────────┴────────────────┴───────╯
subnetCalc 10.12.34.56/19 --subnet_size 20 --json
{
"cidr": "10.12.32.0/19",
"firstIP": "10.12.32.1",
"lastIP": "10.12.63.254",
"networkAddr": "10.12.32.0",
"broadcastAddr": "10.12.63.255",
"subnetMask": "255.255.224.0",
"maskBits": 19,
"subnetBits": 11,
"maxSubnets": 2048,
"maxHosts": 8190,
"subnets": [
{
"cidr": "10.12.32.0/20",
"firstIP": "10.12.32.1",
"lastIP": "10.12.47.254",
"networkAddr": "10.12.32.0",
"broadcastAddr": "10.12.47.255",
"subnetMask": "255.255.240.0",
"maskBits": 20,
"subnetBits": 12,
"maxSubnets": 4096,
"maxHosts": 4094
},
{
"cidr": "10.12.48.0/20",
"firstIP": "10.12.48.1",
"lastIP": "10.12.63.254",
"networkAddr": "10.12.48.0",
"broadcastAddr": "10.12.63.255",
"subnetMask": "255.255.240.0",
"maskBits": 20,
"subnetBits": 12,
"maxSubnets": 4096,
"maxHosts": 4094
}
]
}To get started using subnetCalc, put the binary into your preferred OS's $PATH and run it from the command line.
Bug reports, feature requests, and pull requests are welcome but may not be responded to in an even remotely timely manner.
![dependabot[bot] avatar](https://avatars.githubusercontent.com/in/29110?v=4 "dependabot[bot]")
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent