Re: [Dnsmasq-discuss] v6 to v4 switch on fail over on Strict Order

2023-06-02 Thread Petr Menšík 
If the V6 route is missing, UDP packets sent to v6 hosts would fail 
immediately. dnsmasq tries to use usually some resolver, which is 
responding. If v6 timeouts, they should not become such. It tries to 
send query every 20 seconds or 50 queries to all servers. But in 
general, it should work fine on UDP. TCP is more difficult, there are 
unfixed issues.


On 2/16/23 08:42, Gomathi Shankar P S wrote:

Hi Team,
We are facing an issue when we have the following pre-conditions

  * dnsmasq version - 2.83, and is running in strict-order
  * both v6 and v4 nameservers are in the resolv file
  * when v6 route is fails

there is no fail-over fallback to v4 from v6 nameserver for resolution.

I understand that dnsmasq only reaches V6 nameservers (note - we have 
both v6 and v4 nameservers in resolv.dnsmasq) when we have V6 IP.


I haven't seen any code preferring just IPv6 nameservers when there is 
also IPv4. It should treat them equally and choose last_server to be 
used by any response arrived. If that is only IPv4 servers, it should 
choose them.


If that does not happen, can you provide log with --log-queries or pcap 
with recorded responses? I think it should work.




When V6 route fails (but still we have V6 IP), we would like dnsmasq 
to reach V4 nameservers when V6 route is failed. Currently, it 
forwards the domains only to V6 nameservers as we have V6 IPs.


In the case of "no-strict-order", dnsmasq is reaching out to all 
nameservers.
Is it possible to let dnsmasq to reach out V4 nameservers if the route 
fails (no response from V6 nameservers)?


Regards
Gomathi Shankar P S

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--
Petr Menšík
Software Engineer, RHEL
Red Hat,https://www.redhat.com/
PGP: DFCF908DB7C87E8E529925BC4931CA5B6C9FC5CB
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Re: [Dnsmasq-discuss] v6 to v4 switch on fail over on Strict Order

2023-02-18 Thread Geert Stappers 
On Thu, Feb 16, 2023 at 01:12:48PM +0530, Gomathi Shankar P S wrote:
> Hi Team,
> We are facing an issue when we have the following pre-conditions
> 
>- dnsmasq version - 2.83, and is running in strict-order
>- both v6 and v4 nameservers are in the resolv file
>- when v6 route is fails
> 
> there is no fail-over fallback to v4 from v6 nameserver for resolution.
> 
> I understand that dnsmasq only reaches V6 nameservers (note - we have both
> v6 and v4 nameservers in resolv.dnsmasq) when we have V6 IP.

That understanding might be based upon a small data set.

 
> When V6 route fails (but still we have V6 IP), we would like dnsmasq to
> reach V4 nameservers when V6 route is failed. Currently, it forwards the
> domains only to V6 nameservers as we have V6 IPs.
> 
> In the case of "no-strict-order", dnsmasq is reaching out to all
> nameservers.

Yes.


> Is it possible to let dnsmasq to reach out V4 nameservers if the route
> fails (no response from V6 nameservers)?


Yes-no-questions are poor discussion starters.



Groeten
Geert Stappers
-- 
Silence is hard to parse

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