[Dnsmasq-discuss] Reponse time is huge for big payload SRV record on dnsmasq servers

Harish Shetty harish23shetty at gmail.com
Wed May 9 07:48:44 BST 2018


HI

I am upgrading the dnsmasq now,   But I have couple  of more question, I
read somewhere, dnsmasq can cache only A, AAAA records only.. is that
true??  and multiple line caching is not supported.  Is there anyway we can
cache the TCP query??

Regards
Harish Shetty

On Wed, May 9, 2018 at 1:42 AM, Simon Kelley <simon at thekelleys.org.uk>
wrote:

> Check all the servers you have configured. If one is not accepting TCP
> connections, that could delay things whilst the connection attempt times
> out.
>
> If the upstream servers accept TCP connections and reply on them in a
> timely manner, I don't know what else could be causing the problem. It
> would be worth setting --log-queries to try and see where the delays are.
>
> 2.48 is very, very old. Can you upgrade?
>
>
> Cheers,
>
> Simon.
>
> On 07/05/18 15:30, Harish Shetty wrote:
> > Hi Simon
> >
> > Thanks for the reply,  Yes you are rite, Truncated bit  is set in the
> > message. I am seeing ";; Truncated, retrying in TCP mode."  in the
> > answer. But it is expected and answer is more than 512 bytes (which is
> > size of UDB packet). TCP port 53 is allowed , but DNS respone time from
> > dnsmasq service is more than 3 sec sometime 4 or 5 sec.  When we query
> > directly upstream server we are seeing the response  on avg of 100 to
> > 200 ms.
> >
> > Is there anyway we can make DNS query faster in dnsmasq  server, because
> > it is making our application timeouts.
> >
> > Regards
> > Harish Shetty
> >
> > On Mon, May 7, 2018 at 7:03 PM, Simon Kelley <simon at thekelleys.org.uk
> > <mailto:simon at thekelleys.org.uk>> wrote:
> >
> >     That's large enough to need TCP.
> >
> >     What I'd expect top happen is that the upstream server returns an
> answer
> >     with the truncated bit setin the header. This answer gets returned by
> >     dnsmasq to the original requestor. The original requestor makes a TCP
> >     connection to dnsmasq and re-sends the query. Dnsmasq makes a TCP
> >     connection upstream and send the query, and gets the result. It then
> >     send the result back down the TCP connection to the original
> requestor.
> >
> >     Anything blocking or distrupting TCP connections on port 53 is
> suspect.
> >     An non-responsive upstream server will cause delays whilst the
> >     connection times out.
> >
> >     Try running the query direct to the upstream servers using dig +vc
> >
> >     Cheers,
> >
> >     Simon.
> >
> >
> >     On 07/05/18 13:57, Harish Shetty wrote:
> >     > Hi All
> >     >
> >     > I  am facing some issue with dnsmasq. Currently I am using
> >     dnsmasq-2.48
> >     > ,  I am using this as my forwarder and caching sever. But my
> >     problem is,
> >     > when i query for a high payload SRV record  (answer size is about
> 3500
> >     > bytes) response time some times crosses 4000ms, and intermittently
> >     timeout.
> >     >
> >     > I have tried enabling the logquries, but it didnt give much
> >     information
> >     > to me,  Any suggestion on the debugging or more details will be
> >     helpful
> >     >
> >     > Regards
> >     > Harish Shetty
> >     >
> >     >
> >     >
> >     >
> >     > _______________________________________________
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> >     >
> >
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> >
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