ashok.g has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

I have the following perl code:
  use Nmap::Scanner;
  my $scan = Nmap::Scanner->new();
  $scan->add_target('localhost');
  $scan->add_scan_port('16310-16316');
  $scan->tcp_syn_scan();
  my $results = $scan->scan();

[download]

But it is throwing error:
[root@station19 ~]# perl nmap.pl 
<nmap-error>
  <pid="8711"/>
  <cmdline="'/usr/bin/nmap' -v -v -v -sS -p 16310-16316 -oX - localhos
+t"/>
  <nmap-err>mass_dns: warning: Unable to determine any DNS servers. Re
+verse DNS is disabled. Try using --system-dns or specify valid server
+s with --dns_servers
</nmap-msg>
</nmap-error>

[download]

and the output when I run the nmap command from command line is:
[root@station19 ~]# '/usr/bin/nmap' -v -v -v -sS -p 16310-16316 -oX - 
+localhost
<?xml version="1.0" ?>
<?xml-stylesheet href="/usr/share/nmap/nmap.xsl" type="text/xsl"?>
<!-- Nmap 4.11 scan initiated Tue Jan  3 16:17:13 2012 as: /usr/bin/nm
+ap -v -v -v -sS -p 16310-16316 -oX - localhost -->
<nmaprun scanner="nmap" args="/usr/bin/nmap -v -v -v -sS -p 16310-1631
+6 -oX - localhost" start="1325587633" startstr="Tue Jan  3 16:17:13 2
+012" version="4.11" xmloutputversion="1.01">
<scaninfo type="syn" protocol="tcp" numservices="7" services="16310-16
+316" />
<verbose level="3" />
<debugging level="0" />
mass_dns: warning: Unable to determine any DNS servers. Reverse DNS is
+ disabled. Try using --system-dns or specify valid servers with --dns
+_servers
<host><status state="up" />
<address addr="127.0.0.1" addrtype="ipv4" />
<hostnames><hostname name="localhost.localdomain" type="PTR" /></hostn
+ames>
<ports><port protocol="tcp" portid="16310"><state state="open" /></por
+t>
<port protocol="tcp" portid="16311"><state state="open" /></port>
<port protocol="tcp" portid="16312"><state state="open" /></port>
<port protocol="tcp" portid="16313"><state state="open" /></port>
<port protocol="tcp" portid="16314"><state state="open" /></port>
<port protocol="tcp" portid="16315"><state state="open" /></port>
<port protocol="tcp" portid="16316"><state state="open" /></port>
</ports>
</host>
<runstats><finished time="1325587633" timestr="Tue Jan  3 16:17:13 201
+2"/><hosts up="1" down="0" total="1" />
<!-- Nmap run completed at Tue Jan  3 16:17:13 2012; 1 IP address (1 h
+ost up) scanned in 0.010 seconds -->
</runstats></nmaprun>

[download]

So, running from command line is giving some warning but still continuing and giving me the output which I want. But not the perl code. Is there anyway that I can get this perl code to be working?

Thanks,
Ashok

Replies are listed 'Best First'.
Re: Problem with Nmap::Scanner
by grumbert (Scribe) on Jan 03, 2012 at 11:23 UTC
    Well that test script works for me (running as root) 
    #!/usr/bin/perl

use warnings;

use Nmap::Scanner;
use Data::Dumper;

my $scan = Nmap::Scanner->new();
$scan->add_target('localhost');
$scan->add_scan_port('16310-16316');
$scan->tcp_syn_scan();
my $results = $scan->scan();

print Dumper($results);

    [download]
    ~# ./test.pl 
$VAR1 = bless( {
                 'ALLHOSTS' => {
                                 'Nmap::Scanner::Address=HASH(0x19a186
+0)' => bless( {
                                                                      
+                'ports' => {
..snip...                                            'Nmap::Scanner::P
+ort' ),
...

    [download]
    (I truncated the answer as it's rather too verbose, but rest assured it's showing the port status) This is using Nmap::Scanner 1.0 
    # perl -v

This is perl 5, version 12, subversion 4 (v5.12.4) built for x86_64-li
+nux-gnu-thread-multi
(with 45 registered patches, see perl -V for more detail)

    [download]
    standard perl that comes with Ubuntu 11.10 (64bit) 
    # nmap -V

Nmap version 5.21 ( http://nmap.org )

    [download]
[reply]
[d/l]
[select]
      Hmm...... Do you think this may be due to my DNS settings?
[reply]
Re: Problem with Nmap::Scanner
by Khen1950fx (Canon) on Jan 03, 2012 at 12:26 UTC
    Using pair.perlmonks: 
    #!/usr/bin/perl

use warnings;
use strict 'refs';
use Nmap::Scanner;
use Data::Dumper::Concise;

my $scan = Nmap::Scanner->new();
$scan->tcp_syn_scan();
$scan->add_scan_port(16310-16316);
$scan->add_target('209.197.123.153');
  
my $results = $scan->scan();
print Dumper( $results );

    [download]
    Note the ordering of $scan.
[reply]
[d/l]
      I am able to figure this out. As suspected this is the problem with my DNS servers. After adding DNS servers to my server I am able to get the results of my code.

      Anyways thanks for your help.

      Thanks,
      Ashok.
[reply]

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