[musl] Clarification on the NOERROR resolving choices

[Rob de Wit <rob.dewit@coosto.com>]

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Hi

I ran into some issues lately and found this in the mailing list archive
https://www.openwall.com/lists/musl/2019/05/30/3

The problem I had was with Alpine containers that suddenly failed resolving
any hostname. I ended up tracing it back to a change I made in a domain
that was in the "search" fiels in /etc/resolv.conf. The change was a
wildcard TXT field. So when the resolver was resolving
<host>.<tld>.<searchdomain>.<tld> it received an NOERROR reply. This
indicates there is a record but just not a "A" or "AAAA" one. Perfectly
valid as far as I know, but the resolver then quits the search.

Maybe someone here can clarify this behaviour, because from the referred
thread in the mailing list I get that this is caused by malfunctioning DNS,
but in my case I don't think it is.

Right now our options are:

   - adjusting ndots in resolv.conf - but we actually use the search path
   - adding a dot at the end - this can only work if we know up front we
   don't want the search path
   - replacing Alpine with some libc-based image - this involves many
   changes
   - not to do it again (adding wildcard for something other than A or AAAA
   records)



Met vriendelijke groet / Kind regards

*Rob de Wit*

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