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

This may relate more to OO than Net::DNS...
I'm trying to confirm that DNS updates are being propagated to other nameservers. Net::DNS POD provides this example of lookup, which works fine : 
   use Net::DNS;
   $res = new Net::DNS::Resolver;
   $query = $res->search("foo.bar.com");
   if ($query) {
       foreach $rr ($query->answer) {
           next unless $rr->type eq "A";
           print $rr->address, "\n";
       }
   }
   else {
       print "query failed: ", $res->errorstring, "\n";
   }

[download]
and Net::DNS::Resolver provides this example of querying multiple nameservers : 
   $res->nameservers("192.168.1.1", "192.168.2.2", "192.168.3.3");

[download]
My humble question to the master monks - how do I inject the Net::DNS::Resolver snippet into the Net::DNS query ?
    cheers,
    ybiC

Replies are listed 'Best First'.
DNS Querying Multiple Resolvers in Series - Re: OO
by lhoward (Vicar) on Jun 30, 2000 at 02:05 UTC
    You are very close. To query each nameserver once, put your nameservers in a list and iterate through the list, assigning each nameserver once to a resolver and querying it. See the following: 
    use Net::DNS;
use strict;

my @nameservers=("192.168.1.1", "192.168.2.2", "192.168.3.3");
my $nameserver;
foreach $nameserver(@nameservers){
  print "checking on $nameserver\n";
  my $res = new Net::DNS::Resolver;
  $res->nameservers($nameserver);
  my $query = $res->search("www.perlmonks.com");
  if ($query) {
    my $rr;
    foreach $rr ($query->answer) {
      next unless $rr->type eq "A";
      print $rr->address, "\n";
    }
  }else {
    print "query failed: ", $res->errorstring, "\n";
  }
}

    [download]
    If you assign multiple nameservers to one resolver, it will use them as alternate nameservers in case it doesn't hear back from one of the others.
[reply]
[d/l]
Re: OO (alternate, not multiple, nameservers)
by ybiC (Prior) on Jun 30, 2000 at 03:23 UTC
    Thanks lhoward, that's it to a tee. Alternate namesevers (same as resolv.conf) occured to me as soon as I posted the question. Wasn't as close as I thought.

    I've got MX record and authoritative nameserver query working. With a bit more tweaking (timestamp, reverse lookup, taint+strict cleanup), I'll be ready to post this marginally useful script on Code or Craft.

[reply]

Back to Seekers of Perl Wisdom