Re: After enabling IPv6 curl github.com fails, succeeds with IPv4

[Martin Husemann <martin%duskware.de@localhost>]

On Wed, Jul 22, 2026 at 09:58:45AM +0530, Mayuresh wrote:
> But retrying the identical lookup is a problem anyway (mentioned in
> Christof's mail). I'll file a PR for this. Request views on the above
> point, that will help decide the scope of the PR.

So we have a /etc/resolv.conf that does not contain "domain" or "search"
statements. This used to be a rare case, but with single VPSes deployed at
hosters it may become more likely. I hadn't thought about it, but I have
a similar setup. Out of old habbits I put the machine in one of the
domains it provides services for (muscle memory) and set both the
hostname fully qualified for that domain, as well as the "domain"
entry in /etc/resolv.conf accordingly.

We have two cases:

 - hostname has no dot: the resolver misbehaves and sends two (identical)
   queries instead of just one. This is ineffective, but not very
   serious

 - hostname contains a dot: the resolver halluzinates a domain and
   searches that w/o being told so. This is very bad (as you saw
   from the failure) but there is a configurable workaround

I think both are bugs, but there might be old configurations that depend
on them and changing behaviour always comes with a risc.

Martin