First of, I assume your IP address is actually valid and in the format you mention in your post.

Now for your problem: why make life hard? The code below is quite simple:

   my @bytes = split(/\./, $ip);
   if ($bytes[2] <= 55 && $bytes[3] <= 55) {
      # ok
   }
[download]

You may -- or even should -- want to look at Net::IP, especially at the bincomp function.

Hope this helps, -gjb-