John Rudd wrote:
I'm a prophet now!?
:-)
Hm. So, I'm sure I can figure this out eventually, but does anyone
know the right Net::DNS way to extract the TTL?
Net::DNS::RR has a ttl() function.
# perl ttl_test
Lookup: A www.uribl.com
www.uribl.com 591 IN A 209.200.135.149
--------------------------------------------------------
use Net::DNS;
my $res = Net::DNS::Resolver->new;
&lookup('www.uribl.com', 'A');
exit;
sub lookup {
my ($host, $rr) = @_;
print "Lookup: $rr $host\n";
my $packet = $res->send($host, $rr);
return unless $packet;
my $header = $packet->header;
return if ($header->rcode =~ m/NXDOMAIN|SERVFAIL|REFUSED/i);
my @answer = $packet->answer;
foreach $a (@answer) {
my $type = $a->type;
my $ttl = $a->ttl;
if ($type eq 'A') {
print "$host $ttl IN $a ", $a->address, "\n";
}
# support other rr types below...
}
}
Note that Net::DNS returns the ttl from the answer record, which means
if you have a caching nameserver, your ttl may be lower than the value
returned from the authoritative nameservers. Pulling a ttl from an SOA
wont work either, as ttl can be set per RR. The only proper way to do
this is to perform a lookup, set the $res->nameservers() to those from
the $packet->authority and re-run the query. That will give you
authoritative results, and the ttl will be the proper one.
Something like this...
@authority = $packet->authority;
if (scalar @authority) {
@ns=(); # reset nameservers...
foreach my $a (@authority) {
my $type = $a->type;
my $s = $a->rdatastr;
if ($type =~ m/ns/i) {
$s=~s/\.$//;
push(@ns,$s);
}
}
$res->nameservers(@ns);
}
Pulling authoritative results can be quite slow, so you may want to
alarm it to prevent timeouts from hanging you up.
--
Dallas Engelken
[EMAIL PROTECTED]
http://uribl.com
