[Pdns-dev] My Backend Getting called multiple times

[Nikhil Bose]

Thanks Ruben,

Also if I am serving only A records from my backend, and if my backend is a
bit slow, then is there some place I can set a timeout before PowerDNS
calls my lookup.

As from the example in Writer's guide, suppose I am only serving A records,
but if my backend is slow, PDNS queries again for the A record, that means
my else part will hit again if my backend is slow,
so is there any timeout I can set before PDNS queries back to my backend.

Thanks,
Nikhil

void lookup(const QType &type, const string &qdomain, DNSPacket *p, int zoneId)
  {
    if(type.getCode()!=QType::A || qdomain!="random.powerdns.com")  //
we only know about random.powerdns.com A
      d_answer="";                                                  // no answer
    else {
      ostringstream os;
      os<<random()%256<<"."<<random()%256<<"."<<random()%256<<"."<<random()%256;
      d_answer=os.str();                                           //
our random ip address
    }
  }



On Fri, Nov 16, 2012 at 4:29 PM, Ruben d'Arco <cyclops at prof-x.net> wrote:

> Hi Nikhil,
>
> This is by design. PowerDNS will try to get the soa record to see if it is
> authorative for the domain. It will also try to move up to the root to see
> if a backend is authorative for that. If it is, it will continue with the
> actual records it needs.
> Also, for things like CNAME and MX, it will try to resolve those as well.
>
> So, it is normal and canot be avoided. Just implement the fuctions as
> described in the backend writers guide and powerdns does the rest for you!
>
> Regards,
>      Ruben
>
> Nikhil Bose <nikhilbose11 at gmail.com> wrote:
>
> >Hi All,
> >
> >First of all thanks for the help provided. As Peter in one of my
> >earlier
> >queries gave me a pointer and following that it is quite trivial to
> >create
> >our own Backend in PowerDNS and using getRemote(), I was able to
> >retrieve
> >the Client's resolver IP.
> >
> >PowerDNS is indeed quite simple to extend. Thanks for this
> >architecture.
> >
> >I have one problem though. My backend is getting called multiple times.
> >Even though I just send a single query using the host command.
> >Just to show I put some output statements and these are printed after I
> >sent the client query
> >
> >Here's the console output:
> >
>
> >***************************************************************************************
> >Nov 16 11:20:26 Creating backend connection for TCP
> >Constructor called
> >% Nov 16 11:20:26 [bindbackend] Parsing 1 domain(s), will report when
> >done
> >Nov 16 11:20:26 [bindbackend] parsing 'example.com' from file
> >'/etc/bind/example.com.zone'
> >Nov 16 11:20:26 [bindbackend] Done parsing domains, 0 rejected, 1 new,
> >0
> >removed
> >Constructor called
> >Nov 16 11:20:26 About to create 3 backend threads for UDP
> >Constructor called
> >Constructor called
> >Constructor called
> >Constructor called
> >Constructor called
> >Constructor called
> >Nov 16 11:20:26 Done launching threads, ready to distribute questions
> >Nov 16 11:20:35 Distributor misses a thread (4<5), spawning new one
> >looked up
> >looked up
> >looked up
> >looked up
> >Constructor called
> >Constructor called
>
> >***************************************************************************************
> >
> >How I can reduce this to a single lookup() call from the PowerDNS to my
> >Backend?. Even constructor is called many times. Can this be configured
> >anywhere?
> >
> >Thanks,
> >Nikhil.
> >
> >
> >------------------------------------------------------------------------
> >
> >_______________________________________________
> >Pdns-dev mailing list
> >Pdns-dev at mailman.powerdns.com
> >http://mailman.powerdns.com/mailman/listinfo/pdns-dev
>
> --
> Regards,
>           Ruben
>
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