$ perl -wE'say 5.5*1024 / length("Nov 17 11:09:25 proxy02 kernel: OUTPUT LOGIN= OUT=eth0 SRC=11.11.11.0 DST=192.168.3.1 LEN=1420 TOS=0x00 PREC=0x00 TTL=64 ID=10523 DF PROTO=TCP SPT=3128 DPT=1921 WINDOW=16659 RES=0x00 ACK URGP=0\n")'
29.0309278350515

##</code><code>##

$ perl -MDevel::Size=total_size -wE'my %h; for (1..100) { ++$h{ pack "C4", 1,2,3,$_ } } say total_size(\%h)/100'
47.56

##</code><code>##

use strict;
use warnings;

my $fn_in = 'internal.out';
my $fn_ex = 'external.out';

my @internals = (
    [ pack('C4', 10,0,0,0     ), pack('C4', 255,0,0,0     ) ],
#   [ pack('C4', 10,10,0,0    ), pack('C4', 255,255,0,0   ) ],
    [ pack('C4', 192,3,3,0    ), pack('C4', 255,255,254,0 ) ],
    [ pack('C4', 192,168,0,0  ), pack('C4', 255,255,0,0   ) ],
#   [ pack('C4', 192,168,24,0 ), pack('C4', 255,255,248,0 ) ],
);

sub is_internal {
    my $packed_ip = shift;
    for (@internals) {
        return 1 if $packed_ip & $_->[1] eq $_->[0];
    }
    return 0;
}

sub extract {
    open(my $fh_in, '>', $fn_in)
        or die("Can't create file $fn_in: $!\n");
    open(my $fh_ex, '>', $fn_ex)
        or die("Can't create file $fn_ex: $!\n");

    my %seen;
    while (<>) {
        my $ip = /DST=(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})/
            or next;
        my $packed_ip = pack('C4', split(/\./, $ip));
        next if $seen{$packed_ip}++;
        print { is_internal($packed_ip) ? $fh_in : $fh_ex } "$ip\n";
    }

    undef %seen;  # Free mem.
}


sub sort {
    my ($fn) = @_;

    my @packed_ips;

    {
        open(my $fh, '<', $fn)
            or die("Can't open file $fn: $!\n");
        while (<$fh>) {
            chomp;
            my $packed_ip = pack('C4', split(/\./, $ip));
            push @packed_ips = $packed_ip;
        }
    }

    @packed_ips = sort @packed_ips;

    {
        open(my $fh, '>', $fn)
            or die("Can't create file $fn: $!\n");
        for (@packed_ips) {
            my $ip = join('.', unpack('C4', $packed_ip));
            print("$ip\n");
        }
    }
}


sub main {
    extract();
    sort_file($fn_in);
    sort_file($fn_ex);
}


main();