List of CIDR notation IP blocks, like "172.30.0.0/16".

This class is primarily useful for managing IP whitelists or blacklists. For example, you can check if an address is on a subnet like this:

$whitelist = PhutilCIDRList::newList(array('172.30.0.0/16'));
$ok = $whitelist->containsAddrsss('172.30.0.1');