DNS Resolver result from multiple nameservers - perl

Question

I am passing two name servers to the Net::DNS::Resolver constructor but I am getting only one result back.
How should I change the code to receive result from all the name servers?
sub resolve_dns()
{
my $dns = $_[0];
my $res = Net::DNS::Resolver->new(
nameservers => [qw(24.116.197.232 114.130.11.67 )],
recurse => 0,
debug => 1,
tcp_timeout => 3
);
my $query = $res->search($dns);
if ($query) {
foreach my $rr ($query->answer) {
next unless $rr->type eq "A";
print $rr->address, "\n";
}
} else {
warn "query failed: ", $res->errorstring, "\n";
}
}

Answer 1

I presume the DNS servers after the first are there for fallback purposes and only a single reply will ever be returned.
The best way seems to be to manipulate the Net::DNS::Resolver server list and explicitly make a request to each of them.
This example code demonstrates the principle
sub resolve_dns {
my $address = shift;
my $res = Net::DNS::Resolver->new
recurse => 0,
debug => 1,
tcp_timeout => 3,
);
for my $ns (qw( 24.116.197.232 114.130.11.67 )) {
$res->nameservers($ns);
my $reply = $res->send($address);
if ($reply) {
my #type_a = grep $_->type eq 'A', $reply->answer;
print $_->address, "\n" for #type_a;
}
else {
warn sprintf "Query to %s failed: %s\n", $ns, $res->errorstring;
}
}
}