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

[Simon Kelley]

On 09/05/18 07:48, Harish Shetty wrote:
> 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??  

A, AAAA (some) PTR and CNAME


and multiple line caching is not supported.  Is there anyway we

Not sure what you mean by "multiple line"


Simon.

> can cache the TCP query??
> 
> Regards
> Harish Shetty
> 
> On Wed, May 9, 2018 at 1:42 AM, Simon Kelley <simon at thekelleys.org.uk
> <mailto: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>
>     > <mailto: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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