findstr() and findstr_in_list().
This means that rather than listing an IP address range using the traditional
wildcard characters (e.g. "192.168.1.*"), you could specify a subnet range
using CIDR notation (e.g. "192.168.1.0/24").
The '!' prefix is supported for CIDR match lines (for negated match results),
but no other wildcard/match characters are (e.g. '^', '~', or '*').
You can mix and match traditional match lines and CIDR match lines in the same
filter file.
IPv6 CIDR notation is not yet supported.