here's one quickie on your todo list (still new at perl, 3 months exp.), but just tryin to help, let me know if it's too ugly :)

stick this after your intial quad-dotted number check (second die statement)

my(@ip_pieces) = split /\./,  $seed_ip;
my($piece);

foreach $piece (@ip_pieces) {
    die("ip out of valid range!") if(($piece < 0) || ($piece > 255));
}
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