Getting list IPs from CIDR notation in PHP

Question

Is there a way (or function/class) to get the list of IP addresses from a CIDR notation?

For example, I have 73.35.143.32/27 CIDR and want to get the list of all IP\

Answer 1

Well, it's a bitmask - 73.35.143.32/27 means that 27 bits are the network mask, and the rest is available for assigning to the nodes in the network:

73.35.143.32

in binary is this (dots shown for legibility):

01001001.00100011.10001111.00100000

The netmask is 27 bits:

11111111.11111111.11111111.11100000

So you can just AND them together and get this:

01001001.00100011.10001111.001 00000
 network prefix (27 bits)     | node address (5 bits)

From here, you can just enumerate all the combinations in the node address (00000 is 0, 11111 is 31, so a simple loop is enough), and you'll have all the available hosts.

Converting this pseudocode to PHP is left as an exercise to the reader ;)

Oh, and the obligatory deprecation warning: IPv4 is now full, consider also IPv6.