I'm trying to write a function that tells you if an IP address is in a classless subnet. First of all, has any one already written this code? If not, I'm having trouble with the regex's. Is there an easy way to match a range of numbers like 128-255? I've written it like this, taking advantage of the fact that 255 is the highest possible number:

if ($number =~ /12[89]/ ||$number =~ /1[3-9]\d/ ||$number =~ /2\d\d\/)
+ 
{
            $match = 1;
}
[download]

There must be a better way.

For the more general subnetting problem I'm thinking I probably need to work in binary and doing the AND's and OR's etc. does anyone know of some example Perl code.

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