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(code) Resolve list of DNS names

by ybiC (Prior)
on Jul 11, 2001 at 23:24 UTC ( #95821=sourcecode: print w/ replies, xml ) Need Help??

Category: Networking Code
Author/Contact Info ybiC
Description: Feed this script a textfile list of hostnames, and it spits out CSV and XLS files of names and resolved IP addresses.   I use this ditty to confirm (or deny) in one swell foop that the DNS folks have proper IP address records for every one of the hundred+ LAN switches I support.

Tested with:

  • Net::DNS 0.12
  • Spreadsheet::WriteExcel 0.31
  • Perl 5.00503
  • Debian 2.2r3

Comments and critique are welcome and requested.

Most recent update: 2001-07-12 07:00 CDT
Corrected minor mistakes in comments and above description.
Add a bit more explanation to description above.

#!/usr/bin/perl -w

# resolve.pl
# pod at tail

use strict;
use Net::DNS;
use Spreadsheet::WriteExcel;

my $nameserver = '172.30.4.73';
my %file = (
   in   => 'resolve.in',
   csv  => 'resolve.csv',
   xls  => 'resolve.xls',
   );
my @unlink = (
   $file{csv},
   $file{xls},
   );


# files writable only by this user
umask oct 133;
print "\nStarting $0\n";


# read list of hostnames from input file
unless (-r $file{in} && -T _) {
   print ("Error reading input file \"$file{in}\": $!\n\n");
   &USAGE();
   }
@ARGV = $file{in};
print ("  Reading input file $file{in}\n");
chomp (@ARGV = <>);


# sanity-check input file
# "exit" not "die" so no Perl error to console
print "  Validating target list...\n";
foreach my $nonsane (@ARGV) {
   chomp $nonsane;
   unless ($nonsane =~ (/^(\w|-|\.)+$/)) {
      print(
         "\n  Ack - \"$nonsane\" is improperly formatted.\n",
         "  Only alphanumeric, underscore, dash and dot allowed.\n\n",
         "  Edit $file{in} or re-enter targets to remove puctuation,",
         "blank lines and/or blank spaces.\n\n",
         );
      exit;
      }
   }
   print ("  Specified targets names all valid.\n");


# delete pre-existing out file
for(@unlink) {
   &UNLINK($_, 'verbose');
   }


# get down to business
print "  Resolving names...\n";
open (CSVFILE, ">>$file{csv}") or die "Error opening $file{csv} for ap
+pend: $!";
print CSVFILE "hostname,IPaddr\n";
foreach my $called (@ARGV) {
   my $res = new Net::DNS::Resolver;
   $res->nameservers($nameserver);
   my $query = $res->search("$called");
   if ($query) {
      my $rr;
      foreach $rr ($query->answer) {
         next unless $rr->type eq "A";
         print CSVFILE "$called,", $rr->address, "\n"
        or die "Error printing to $file{csv}: $!";
         }
      } else {
      print CSVFILE "$called,query failed: ", $res->errorstring, "\n"
         or die "Error printing to $file{csv}: $!";
      }
   }
close (CSVFILE) or die "Error closing $file{csv}: $!";


# create Excel binary format outfile from CSV
print ('  Munging csv outfile to xls binary format - ');
open (CSVFILE, $file{csv}) or die "Error opening $file{csv}: $!";
my $workbook  = Spreadsheet::WriteExcel -> new($file{xls});
my $worksheet = $workbook -> addworksheet();
my $row      = 0;
while (<CSVFILE>) {
   chomp;
   my @field = split(',', $_);
   my $column = 0;
   foreach my $token (@field) {
      $worksheet -> write($row, $column, $token);
      $column++;
      }
   $row++;
   }
my $format1 = $workbook -> addformat();
   $format1 -> set_bold();
   $format1 -> set_align('center');
   $format1 -> set_bg_color('tan');
   #$format1 -> set_border();
$worksheet -> set_row(0, undef, $format1);
$workbook  -> close() or die "Error closing $workbook: $!";
print ("done.\n");


# Wrap it all up
print ("Completed run of $0.\nResults at $file{csv} and $file{xls}\n\n
+");
exit;


######################################################################
+#####
# cleanup files when done with them
sub UNLINK {
   my $file = $_[0];
   my $echo = $_[1];
   if (-e $file && -w _) {
      print "  Unlinking $file..."        if ($echo eq 'verbose');
      unlink $file or die "Error unlinking $file: $!";
      print "  *poof*\n"               if ($echo eq 'verbose');
      }
   }
######################################################################
+#####
# don't really need to es'plain this one
sub USAGE {
print <<EOF

Usage : $0 <enter>
      where $file{in} is textfile listing device DNS name, one per lin
+e.

perldoc $0 for a few more details.

    This script              $0
    Net::DNS                 $Net::DNS::VERSION
    Spreadsheet::WriteExcel  $Spreadsheet::WriteExcel::VERSION
    Perl                     $]
    Local OS                 $^O

EOF
   ;
   exit;
   }
######################################################################
+#####


=head1 Name

resolve.pl

=head1 Summary

Feed this script a textfile list of DNS names, and it spits back
CSV and XLS files of names and IPaddrs.

 Comments and critique are always welcomed.

=head1 Usage

 resolve.pl <enter>

=head1 Tested

 Net::DNS                 0.12
 Spreadsheet::WriteExcel  0.31
 Perl                     5.00503
 Debian                   2.2r3

=head1 Updated

 2001-07-11   17:25 CDT
   Correct minor mistakes in comments.
   Post to PerlMonks.
   Initial working code.

=head1 ToDos

 Accept IPaddrs from infile and resolve to name.

=head1 Author

 ybiC

=cut



Comment on (code) Resolve list of DNS names
Download Code
Re: Resolve list of DNS names
by mikeB (Friar) on Jul 11, 2001 at 23:53 UTC
    Check out this recent thread on validating IP addresses. It's not quite as simple as you might think.
      Thanks for the thread-link, mikeB.   8^)

      However, my infile sanity-check isn't intended to parse or untaint IP addresses.   If I ever do add support for IP address input (reverse-lookups), I'll likely look to CPAN for a module.   A quick search turned up these candidates: Net::IPAddr-Find, Net::IPv4Addr, Net::IP, and NetAddr::IP.
          cheers,
          Don
          striving toward Perl Adept
          (it's pronounced "why-bick")

        Get the following error. What should i do? print (...) interpreted as function at ./resolve.pl line 112. syntax error at ./resolve.pl line 120, near "sub UNLINK " Can't use global @_ in "my" at ./resolve.pl line 121, near "= $_" syntax error at ./resolve.pl line 128, near "}" Execution of ./resolve.pl aborted due to compilation errors.

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