elsifsheep has asked for the wisdom of the Perl Monks concerning the following question:

I'm trying to use IPv6 addresses in Net::DNS::Resolver and it's not working. Help? 
%tld_v4_masters = (
        "server1" => "10.1.1.1",
        "server2" => "10.1.1.2",
        "server3" => "10.1.1.3",
        "server4" => "10.1.1.4",
);
%tld_v6_masters = (
        "server1" => "2620:10a:aaaa::1",
        "server1" => "2620:10a:aaaa::2",
        "server1" => "2620:10a:aaaa::3",
        "server1" => "2620:10a:aaaa::4",
);


######################################################################
+####################
### SUB: &verifymasters; - Verify and Determine which zone masters to 
+compare myself against
######################################################################
+####################
sub verifymasters {
print "Running verifymasters...\n";
  foreach $tryzm (values %$prizms) {
    print "[DEBUG(verifymasters)] Verifying ZM $tryzm with test candid
+ate zone $testcandidate...\n" if ($debug);
    $res = new Net::DNS::Resolver;
    $res->tcp_timeout (1) ;
    $res->retry (1) ;
    $res->retrans (1) ;
    $query = $res->nameservers($tryzm);
    $query = $res->query($testcandidate, "SOA");
    my $serial=($query->answer)[0]->serial, if ($query);
    if (length($serial) > 2) {
      print "[DEBUG(verifymasters)] Marking ZM $tryzm as GOOD!\n" if (
+$debug);
      $goodzms++;
    }
    else {
      print "[DEBUG(verifymasters)] Marking ZM $tryzm as BAD!\n" if ($
+debug);
    }
  }
  if ($goodzms < 4) {
    foreach $tryzm (values %$seczms) {
      print "[DEBUG(verifymasters)] Verifying ZM $tryzm with test cand
+idate zone $testcandidate...\n" if ($debug);
      $res = new Net::DNS::Resolver;
      $res->tcp_timeout (1) ;
      $res->retry (1) ;
      $res->retrans (1) ;
      $query = $res->nameservers($tryzm);
      $query = $res->query($testcandidate, "SOA");
      my $serial=($query->answer)[0]->serial, if ($query);
      if (length($serial) > 2) {
        print "[DEBUG(verifymasters)] Marking ZM $tryzm as GOOD!\n" if
+ ($debug);
        $goodzms++;
      }
      else {
        print "[DEBUG(verifymasters)] Marking ZM $tryzm as BAD!\n" if 
+($debug);
      }
    }
  }
}

[download]
I end up with the IPv4 checks being marked as GOOD, an the IPv6 tests being marked as BAD.

Replies are listed 'Best First'.
Re: Net::DNS::Resolver using IPv6 transport in nameservers
by elsifsheep (Novice) on Jul 09, 2020 at 17:25 UTC
    I can't explain this behaviour... 
    #!/usr/bin/perl

use Net::DNS;
#use IO::Socket::IP;

$testcandidate="cl";


print "IPV4 test...\n";
      $res = new Net::DNS::Resolver;
      $res->tcp_timeout (1) ;
      $res->retry (1) ;
      $res->retrans (1) ;
      $query = $res->nameservers('162.219.53.120');
      $query = $res->query($testcandidate, "SOA");
      print "What's in the array: \n";
      print join ' ', $res->nameservers();
      print "\n";
      my $serial=($query->answer)[0]->serial, if ($query);
      print "serial:  $serial\n";

print "\n\nIPV6 test...\n";
      $res = new Net::DNS::Resolver;
      $res->tcp_timeout (1) ;
      $res->retry (1) ;
      $res->retrans (1) ;
      $query = $res->nameservers('2620:10a:80d1:1053::120');
      $query = $res->query($testcandidate, "SOA");
      print "What's in the array: \n";
      print join ' ', $res->nameservers();
      print "\n";
      my $serial=($query->answer)[0]->serial, if ($query);
      print "serial:  $serial\n";

    [download]
    Which outputs... 
    [root@ns01 jzack]# ./snippet 
IPV4 test...
What's in the array: 
162.219.53.120
serial:  2020070925


IPV6 test...
What's in the array: 

serial:

    [download]
    How is it that the IPv6 address isn't even being mentioned when I print the array elements? I thought I was debugging a Net::DNS issue...but it seems I must be doing something wrong with arrays in general? When I throw this into debug, I see: IPV6 test... ;; query(cl, SOA) ;; setting up an AF_INET() family type UDP socket So how do I get it to not use AF_INET?
[reply]
[d/l]
[select]
      The answer to my question was: The Net::DNS::Resolver library will use IPv6 transport if the appropriate libraries (Socket6 and IO::Socket::INET6) are available and the address the server tries to connect to is an IPv6 address. Self-solved.
[reply]
        >Self-solved.

        Congrats, that's always the best kind of solved. =D Just replying so you didn't look like you were talking to yourself any more than the rest of us.

[reply]

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