Net::DNS failure on RHEL6

[neilwatson]

UPDATE: Fixed. Problem was not Perl. Permissions were incorrect on /etc/nsswitch.conf which prevented Perl from using it.

Grettings,

Some code that uses Net::DNS works on RHEL5 hosts, (Net::DNS 0.59), but fails (query is undef) on RHEL6 (Net::DNS 0.65). What might the problem be?

Code sample:

#!/tool/pandora64/bin/perl5.8.8

use Net::DNS;
use Data::Dumper;
use strict;
use warnings;

my $host = $ARGV[0];

my @domains;
open(RESOLV, "/etc/resolv.conf") or die("couldn't open /etc/resolv.con
+f for reading!");
while(<RESOLV>) {
    next unless /^search\s+(.*)/;
    my $str = $1;
    @domains = split(/\s+/, $str);
}
close RESOLV;

my $res = new Net::DNS::Resolver;
$res->debug(1);
# Remove all subdomain stuff
$host =~ s/\..*//g; 

# Now figure out the FQDN by choosing from the entries in resolv.conf.
my ( $fqhost, $query );
foreach(@domains) {
    print "query -> $host.$_\n";
    $query = $res->query("$host.$_");
    if($query) {
        $fqhost = $host . "." . $_;
        last;
    }
}
unless(defined $fqhost) {
    print Dumper( \@domains );
    print Dumper( \$query );
    # If we can't resolve the IP for a given hostname,
    # we skip that host completely.
    die "WARNING: Skipping host: $host, query: $query -- no DNS entry!
+";
}

RHEL5 output:

$ dnscheck.pl atlrhel5cs
query -> atlrhel5cs.example.com
;; query(atlrhel5cs.example.com)
;; setting up an AF_INET() family type UDP socket
;; send_udp(127.0.0.1:53)
;; answer from 127.0.0.1:53 : 52 bytes
;; HEADER SECTION
;; id = 32277
;; qr = 1    opcode = QUERY    aa = 0    tc = 0    rd = 1
;; ra = 1    ad = 0    cd = 0    rcode  = NOERROR
;; qdcount = 1  ancount = 1  nscount = 0  arcount = 0

;; QUESTION SECTION (1 record)
;; atlrhel5cs.example.com.  IN      A

;; ANSWER SECTION (1 record)
atlrhel5cs.example.com.     9270    IN      A       10.180.10.46

;; AUTHORITY SECTION (0 records)

;; ADDITIONAL SECTION (0 records)

$VAR1 = \bless( {
                   'answer' => [
                                 bless( {
                                          'rdlength' => 4,
                                          'ttl' => 9270,
                                          'name' => 'atlrhel5cs.exampl
+e.com',
                                          'address' => '10.180.10.46',
                                          'class' => 'IN',
                                          'type' => 'A',
                                          'rdata' => '
�
.'
                                        }, 'Net::DNS::RR::A' )
                               ],
                   'buffer' => undef,
                   'question' => [
                                   bless( {
                                            'qclass' => 'IN',
                                            'qname' => 'atlrhel5cs.exa
+mple.com',
                                            'qtype' => 'A'
                                          }, 'Net::DNS::Question' )
                                 ],
                   'answerfrom' => '127.0.0.1',
                   'answersize' => 52,
                   'additional' => [],
                   'authority' => [],
                   'header' => bless( {
                                        'nscount' => 0,
                                        'cd' => 0,
                                        'qdcount' => 1,
                                        'ancount' => 1,
                                        'rcode' => 'NOERROR',
                                        'tc' => 0,
                                        'opcode' => 'QUERY',
                                        'ad' => 0,
                                        'ra' => 1,
                                        'qr' => 1,
                                        'arcount' => 0,
                                        'id' => 32277,
                                        'aa' => 0,
                                        'rd' => 1
                                      }, 'Net::DNS::Header' ),
                   'offset' => undef
                 }, 'Net::DNS::Packet' );

RHEL6 output:

~$ dnscheck.pl atlrhel5cs
query -> atlrhel5cs.example.com
;; query(atlrhel5cs.example.com)
;; setting up an AF_INET() family type UDP socket
query -> atlrhel5cs.to.example2.com
;; query(atlrhel5cs.to.example2.com)
;; setting up an AF_INET() family type UDP socket
query -> atlrhel5cs.example2.com
;; query(atlrhel5cs.example2.com)
;; setting up an AF_INET() family type UDP socket
$VAR1 = [
          'example.com',
          'to.example2.com',
          'example2.com'
        ];
$VAR1 = \undef;
Use of uninitialized value in concatenation (.) or string at /home/new
+atson/bin/dnscheck.pl line 39.
WARNING: Skipping host: atlrhel5cs, query:  -- no DNS entry! at /home/
+newatson/bin/dnscheck.pl line 39.

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