Cygwin unable to resolve hostnames

Corinna Vinschen
Mon Mar 14 09:55:00 GMT 2016

On Mar 14 09:34, Jun-ya Kato wrote:
> It also depends on AAAA query againt VMware's DNS proxy server.
> For more analysis, see vmware community site,
> I think it is not cygwin's bug at all. but any workaround may be
> implemented againt weak behavior of GetAddrInfoW() API.

As mentioned in the above posting, Cygwin always sets AI_ALL if
ai_family is PF_UNSPEC and the hints don't specify AI_ADDRCONFIG.

Apparently Winsock's GetAddrInfoW chokes on AI_ALL in certain
circumstances.  On GLibc, AI_ALL is ignored if AI_V4MAPPED is not given,
but that's not as I observed it on Windows when I added this code
(back in Vista times, but hey).

There's an easy workaround possible:  If GetAddrInfoW returns the
error code WSANO_RECOVERY (per the above posting), we can retry
without the AI_ALL flag.

Is anybody here affected by this problem willing to give this a test?
I can create another Cygwin 2.5.0 test release pretty soon...


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat
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