#!/usr/bin/perl

use strict;
use warnings;
use XML::Twig;
use Data::Dumper;

my $xml = do{ local $/; <DATA> };

my @hosts;
my $parser  = XML::Twig->new(
    twig_handlers => { 
        'HOST'       => \&hosts,
});
$parser->parse($xml);

print Dumper \@hosts;

sub hosts {
    my ($twig,$host) = @_;
    
    my %hash = (
        ip      => $host->findvalue( 'IP' ),
        dns     => $host->findvalue( 'DNS' ),
        comment => $host->findvalue( 'COMMENT/VALUE' ),
    );
    
    push @hosts, \%hash;
}


__DATA__
<root>
<HOST>
        <IP>192.168.1.1</IP>
        <TRACKING_METHOD>
                <VALUE>IP address</VALUE>
        </TRACKING_METHOD>
        <DNS>dns-server.test.de</DNS>
        <OPERATING_SYSTEM>Linux</OPERATING_SYSTEM>
        <COMMENT>
                <VALUE>Testnetz</VALUE>
        </COMMENT>
        <USER_DEFINED_ATTR_LIST>
                <USER_DEFINED_ATTR>
                                <UDA_INDEX>1</UDA_INDEX>
                                <UDA_TITLE>Ansprechpartner</UDA_TITLE>
                                <UDA_VALUE>Herr Mustermann</UDA_VALUE>
                        </USER_DEFINED_ATTR>
                <USER_DEFINED_ATTR>
                                <UDA_INDEX>2</UDA_INDEX>
                                <UDA_TITLE>Standort</UDA_TITLE>
                                <UDA_VALUE>Testnetz</UDA_VALUE>
                        </USER_DEFINED_ATTR>
        </USER_DEFINED_ATTR_LIST>
</HOST>
</root>