use Socket qw [inet_aton];

sub squish
{
    my($ip_lo,$ip_hi,$name) = split (//,$_[0]);
    return $name.inet_aton($ip_lo).inet_aton($ip_hi);
}

@sorted = sort { squish($a) cmp squish($b) } @unsorted;
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The inet_aton function returns four bytes, the value of the IP address in network order, which sorts properly using an ASCII sort. The Socket module is standard with Perl.