Server 1 111.222.333.444
Server 2 222.333.444.555
Server 3 111.333.444.555

#!/usr/bin/perl

use warnings;
use strict;

my $filename = "test";

sub ipToInt {
    my $ip = shift;
    my $sum = 0;
    # Splitting at dots is tricky:
    my @arr = split('\.', $ip);
    my $i;
    foreach $i (@arr) {
        $sum = $sum * 256 + $i;
    }
    return $sum;
}

sub getIPasNumber {
    my $l = shift;
    chomp($l);
    my @a = split(" ", $l);
    return ipToInt($a[2]);
}

my $fh;
open($fh, "<", $filename) or die;
my @a = <$fh>;
close $fh;

my %h;
my $i;
foreach $i (@a) {
    chomp($i);
    my $num = getIPasNumber($i);
    $h{$num} = $i;
}
foreach $i (sort {$b <=> $a} (keys(%h))) {
    print "$h{$i}\n";
}