Subject: [alpine-user] Support request - Force DNS requests to go over TCP

From: Richard Tweed <[email-masked]>
Date: Fri, 12 Apr 2019 14:00:40 +0100

Hi all,

I've run into a situation where I need DNS resolution to always be over TCP
rather than UDP due to AWS dropping DNS packets frequently enough to be a
problem. On glibc based environments I can use the use-vc option in the
resolv.conf file.
http://man7.org/linux/man-pages/man5/resolv.conf.5.html
On Alpine this doesn't seem to be supported and I would love to hear any
suggestions about achieving this behaviour.

Feel free to CC me on this discussion

Many thanks,

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Richard Finlay Tweed

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From: Paul Bredbury <[email-masked]>
Date: Sat, 13 Apr 2019 10:40:39 +0100

For any non-trivial DNS, I recommend to use Unbound.

If you really need TCP, it has an option:

tcp-upstream: <yes or no>  
Enable or disable whether the upstream queries use TCP only for transport. Default is no. Useful in tunneling scenarios.

On Fri, 2019-04-12 at 14:00 +0100, Richard Tweed wrote:
> I've run into a situation where I need DNS resolution to always be over TCP rather than UDP due to AWS dropping DNS packets frequently enough to be a problem. On glibc based environments I can use
> the use-vc option in the resolv.conf file. 
> On Alpine this doesn't seem to be supported and I would love to hear any suggestions about achieving this behaviour.

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From: Richard Tweed <[email-masked]>
Date: Mon, 15 Apr 2019 10:46:24 +0100

Thanks, I'll check that out!

On Sat, 13 Apr 2019 at 10:40, Paul Bredbury <[email-masked]> wrote:

> Enable or disable whether the upstream queries use TCP only for transport.
> Default is no. Useful in tunneling scenarios.
>
> > I've run into a situation where I need DNS resolution to always be over
> TCP rather than UDP due to AWS dropping DNS packets frequently enough to be
> a problem. On glibc based environments I can use

-- 

Richard Finlay Tweed

--