[Dnsmasq-discuss] REFUSED after dropped packets

Simon Kelley simon at thekelleys.org.uk
Wed Sep 29 09:09:27 UTC 2021



On 28/09/2021 18:08, Johannes Stezenbach wrote:
> On Mon, Sep 27, 2021 at 10:45:25PM +0100, Simon Kelley wrote:
>>
>> I think that this is a 2.86 problem. There are two cases when dnsmasq
>> will try another server with the same query:
>>
>> 1) When a client retries the query.
>> 2) When the first server returns REFUSED.
>>
>> In the second case, it's important to give up when all available servers
>> have returned REFUSED, otherwise the query keeps bouncing forever. 2.86
>> got the two cases mixed up and implemented that behavior for client
>> retries too. That's a bug.
>>
>> https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=2561f9fe0eb9c0be1df48da1e2bd3d3feaa138c2
>>
>> should fix it.
>>
>>
>> Please test.....
> 
> This seems to work well. Currently my Wifi connection is stable,
> thus I disconnected the antenna to simulate the problem:
> 
> $ host kernel.org
> ;; connection timed out; no servers could be reached
> 
> Dnsmasq properly forwarded the client retry:
> 
> Sep 28 19:00:03 dnsmasq[32598]: 4 127.0.0.1/35962 query[A] kernel.org from 127.0.0.1
> Sep 28 19:00:03 dnsmasq[32598]: 4 127.0.0.1/35962 forwarded kernel.org to 192.168.178.1
> Sep 28 19:00:08 dnsmasq[32598]: 5 127.0.0.1/35962 query[A] kernel.org from 127.0.0.1
> Sep 28 19:00:08 dnsmasq[32598]: 5 127.0.0.1/35962 forwarded kernel.org to 192.168.178.1
> 
> 
> After reattaching the antenna:
> 
> $ host kernel.org
> kernel.org has address 198.145.29.83
> kernel.org mail is handled by 10 mail.kernel.org.
> 
> Sep 28 19:00:51 dnsmasq[32598]: 6 127.0.0.1/54047 query[A] kernel.org from 127.0.0.1
> Sep 28 19:00:51 dnsmasq[32598]: 6 127.0.0.1/54047 forwarded kernel.org to 192.168.178.1
> Sep 28 19:00:51 dnsmasq[32598]: 6 127.0.0.1/35962 reply kernel.org is 198.145.29.83
> Sep 28 19:00:51 dnsmasq[32598]: 6 127.0.0.1/54047 reply query is duplicate
> Sep 28 19:00:51 dnsmasq[32598]: 7 127.0.0.1/41845 query[AAAA] kernel.org from 127.0.0.1
> Sep 28 19:00:51 dnsmasq[32598]: 7 127.0.0.1/41845 forwarded kernel.org to 192.168.178.1
> Sep 28 19:00:51 dnsmasq[32598]: 7 127.0.0.1/41845 reply kernel.org is NODATA-IPv6
> Sep 28 19:00:51 dnsmasq[32598]: 8 127.0.0.1/42436 query[MX] kernel.org from 127.0.0.1
> Sep 28 19:00:51 dnsmasq[32598]: 8 127.0.0.1/42436 forwarded kernel.org to 192.168.178.1
> Sep 28 19:00:51 dnsmasq[32598]: 8 127.0.0.1/42436 reply kernel.org is <MX>
> 
> 
> Thanks,
> Johannes
> 


Working well for me too. I think we can tick that one off. Thanks for
your help.

Simon.




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