Aah - yes - I've run into this before.
The Database returns signed 32-bit integers. The high IP addresses show up as negative integers.

I would recommend using a module to handle IP addresses - my favourite is NetAddr::IP which works admirably but it won't solve your problem - you need a little more magic..

Your problem can be solved using this :

  $n = get_number_from_database();
  my $ip = NetAddr::IP->new($n < 0 ? 2**32 + $n : $n);
  # $ip now contain and IP object which can be printed ,
  # or converted to binary, or checked for
  # subnet membership.
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(Thanks to Luis E. Muņoz, author of NetAddr::IP, for the original tip)