cidr

CLI to perform various actions on CIDR ranges

Brew

To install cidr using brew, simply run:

brew install cidr

Binaries

You can download the latest binary for Linux, MacOS, and Windows.

Examples

Using cidr is very simple.

Explain a CIDR range

To get more information on a CIDR range:

$ cidr explain 10.0.0.0/16
Base Address:            10.0.0.0
Usable Address Range:    10.0.0.1 to 10.0.255.254
Broadcast Address:       10.0.255.255
Address Count:           65,534
Netmask:                 255.255.0.0 (/16 bits)

This also works with IPv6 CIDR ranges, for example:

$ cidr explain 2001:db8:1234:1a00::/64
Base Address:            2001:db8:1234:1a00::
Usable Address Range:    2001:db8:1234:1a00:: to 2001:db8:1234:1a00:ffff:ffff:ffff:ffff
Address Count:           18,446,744,073,709,551,614
Netmask:                 ffff:ffff:ffff:ffff:: (/64 bits)

Check whether an address belongs to a CIDR range

To check if a CIDR range contains an IP:

$ cidr contains 10.0.0.0/16 10.0.14.5
true

This also works with IPv6 addresses, for example:

$ cidr contains 2001:db8:1234:1a00::/106 2001:db8:1234:1a00::
true

Count distinct host addresses

To get all distinct host addresses part of a given CIDR range:

$ cidr count 10.0.0.0/16
65534

This also works with a IPv6 CIDR range, for example:

$ cidr count 2001:db8:1234:1a00::/106
4194302

Or with a large prefix like a point-to-point link CIDR range:

$ cidr count 172.16.18.0/31
2

CIDR range intersection

To check if a CIDR range overlaps with another CIDR range:

$ cidr overlaps 10.0.0.0/16 10.0.14.0/22
true

This also works with IPv6 CIDR ranges, for example:

$ cidr overlaps 2001:db8:1111:2222:1::/80 2001:db8:1111:2222:1:1::/96
true

Contributing

Contributions are highly appreciated and always welcome. Have a look through existing Issues and Pull Requests that you could help with.