[Dnsmasq-discuss] Patch with option to filter A records

Geert Stappers stappers at stappers.nl
Fri Jul 9 15:46:11 UTC 2021

On Fri, Jul 09, 2021 at 02:35:29PM +0200, Petr Menšík wrote:
> On 6/16/21 1:26 PM, Trey Sis wrote:
> > On 6/14/2021 1:43, Trey Sis wrote:
> >> On 6/13/2021 22:01, Geert Stappers wrote:
> >>> warning: 1 line adds whitespace errors.
> >>
> >> My bad! Fixed. Find the new patch attached to this message.
> >>
> >
> > Hello everyone,
> >
> > I was wondering if anyone has any suggestions or objections for the
> > patch?
> >
> > I still think it would be very valuable for many setups out there to
> > drop A records. Most OS don't query for AAAA if there is no IPv6
> > connection. But none don't query for A if there is no IPv4. That often
> > causes problems with applications that did not (yet) implement happy
> > eyeballs. Getting this upstream would make it much easier to handle
> > IPv6-only environments.
> >
> > What do you think?
> >
> Hi Trey,
> Are there any specific applications requiring this patch? It seems to me
> most of work should be spent on applications not handling IPv4 addresses
> correctly. Also, I would implement filtering of both address families if
> it is required.
> Are there specific applications, where we can help escalate the problem
> on their side instead?  As you have already said, when they ask for A
> address, they should receive one. Whether it is useful or not, clients
> should be able to process it. And skipping to IPv6 in case of no IPv4
> connectivity should be immediate. We lack full IPv6 connectivity at
> office, so far I know only svn is not able to switch to IPv4 only. Which
> is solved by switching to git. Filtering of AAAA record would have
> solved it too.

Quoting post that started this email thread:

} I have created a patch that adds an option to dnsmasq to filter
} out A record requests. This is particularly suitable for IPv6-only
} environments. Some software (especially NodeJS) will reorder DNS
} requests giving priority to A records,       irrespective of IPv4
} connectivity of the host. My patch filters A records, while AAAA
} records are returned.

Short answer to
> Do you have examples of applications, where this change would help?


Geert Stappers
Silence is hard to parse

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