%host = (

  'ip1' => {
     'tcp' => {
        '21' => {
           'state' => 'open',
           'service' => 'ftp'
        },
        '80' => {
           'state' => 'open',
           'service' => 'web'
        }
      }
    },

  'ip2' => {
     'tcp' => {
        '23' => {
           'state' => 'open',
           'service' => 'telnet'
        },
       '80' => {
           'state' => 'open',
           'service' => 'web'
        }
      }
    }

);

##</code><code>##

foreach $ip (keys %host) {
    print $ip . "\n";
    foreach $type (keys %{$host{$ip}}) {
        foreach $no (keys %{$host{$ip}->{$type}}) {
            print " " . $no . "\t" . $host{$ip}->{$type}->{$no}->{'state'} . "\t" . $host{$ip}->{$type}->{$no}->{'service'} . "\n";
        }
    }
}

##</code><code>##

$host{'ip1'}->{'tcp'}->{53}->{'state'} = 'open';
$host{'ip1'}->{'tcp'}->{53}->{'service'} = 'dns';