cidrl — CIDR List

CIDRL lists all IP addresses within a CIDR block (IPv4 and IPv6.) Supports subnetting.

Classless Inter-Domain Routing (CIDR; rfc1519) is a strategy for assigning and routing Internet Protocol (IP) addresses.

Usage

cidrl for IPv4

Analyse and list all hosts in a /29:

$ man cidrl
$ cidrl -a 192.168.50.16/29
Gateway:    192.168.50.16
Broadcast:  192.168.50.23
Netmask:    255.255.255.248
Hosts:      8
$ cidrl 192.168.50.16/29
192.168.50.16
192.168.50.17
192.168.50.18
192.168.50.19
192.168.50.20
192.168.50.21
192.168.50.22
192.168.50.23

Split a /24 into /28:

$ cidrl -s28 10.0.0.0/24
10.0.0.0/28
10.0.0.16/28
10.0.0.32/28
10.0.0.48/28
10.0.0.64/28
10.0.0.80/28
10.0.0.96/28
10.0.0.112/28
10.0.0.128/28
10.0.0.144/28
10.0.0.160/28
10.0.0.176/28
10.0.0.192/28
10.0.0.208/28
10.0.0.224/28
10.0.0.240/28

See examples/host_exists_in_network.sh for an example on how to use the -e option to programmatically check if a host exists within a given network. Alternatively, use cidrl -ae <host> <network>.

cidrl6 for IPv6

Split an IPv6 /60 into /64:

$ man cidrl6
$ cidrl6 -s64 fa01:0:0:ffa0::/60
fa01:0:0:ffa0::/64
fa01:0:0:ffa1::/64
fa01:0:0:ffa2::/64
fa01:0:0:ffa3::/64
fa01:0:0:ffa4::/64
fa01:0:0:ffa5::/64
fa01:0:0:ffa6::/64
fa01:0:0:ffa7::/64
fa01:0:0:ffa8::/64
fa01:0:0:ffa9::/64
fa01:0:0:ffaa::/64
fa01:0:0:ffab::/64
fa01:0:0:ffac::/64
fa01:0:0:ffad::/64
fa01:0:0:ffae::/64
fa01:0:0:ffaf::/64

Analyse an IPv6 network and check if a given host exists within it:

$ cidrl6 -ae fa01::ffb0:3:0:0:ae90 fa01:0:0:ffa0::/64
Network:    fa01:0:0:ffa0::
Range-end:  fa01::ffa0:ffff:ffff:ffff:ffff
Netmask:    ffff:ffff:ffff:ffff::

The host fa01::ffb0:3:0:0:ae90 does not exist within this network.

Installation

$ git clone git@github.com:emden-norfolk/cidrl.git
$ cd cidrl/
$ make
$ sudo make install

References

The following manual pages are helpful for understanding the implementation of CIDRL:

• getopt.3
• scanf.3
• byteorder.3
• atoi.3
• inet.3
• inet_pton.3
• inet_ntop.3
• ipv6.7

Further reading:

• Grothof, C. (2008), Migrating Code to IPv6 the good, the bad and the ugly, Colorado Research Institute for Security and Privacy.

See also:

• Nmap
• prips

Author

2016 (c) Damien Bezborodov