RE: getaddrinfo fails with EAI_NODATA for some valid hosts with A records

["Andy Hall" <fixpertise-consulting at comcast dot net>]

> -----Original Message-----
> From: cygwin-owner@cygwin.com [mailto:cygwin-owner@cygwin.com] On Behalf Of Brian Inglis
> Sent: Wednesday, January 13, 2016 12:14 AM
> To: cygwin@cygwin.com
> Subject: Re: getaddrinfo fails with EAI_NODATA for some valid hosts with A records
> 
> Corinna Vinschen <corinna-cygwin <at> cygwin.com> writes:
> > On Jan  7 15:39, Brian Inglis wrote:
> >> getaddrinfo fails with err 7 EAI_NODATA for some valid hosts with A records.
> >> Err 7 EAI_NODATA is mapped from WSANO_DATA err 11004 in Windows.
> >> Can anyone reproduce failure with problem host name below?
> >
> > Yes, I can reproduce it, and it's a total surprise.
> 
> > I have no idea why Windows' getaddrinfo chokes on leapsecond.utcd.org
> > at all.
> 
> Especially when after just one getaddrinfo call, the DNS cache is populated
> with:
>     leapsecond.utcd.org
>     ----------------------------------------
>     Record Name . . . . . : leapsecond.utcd.org
>     Record Type . . . . . : 1
>     Time To Live  . . . . : 600
>     Data Length . . . . . : 4
>     Section . . . . . . . : Answer
>     A (Host) Record . . . : 244.34.36.97
> 
> so the DNS server is being contacted and responding normally, but it would
> appear Windows GAI is failing to use that info.
> Has this been reproduced on W10 so we can report this upstream?
> Is there any support without an account for upstream W7 reports?
> 
> 
DNS just translates URLs to IP addresses.  It is no surprise that works.   However, addresses in the range 240.0.0.0 -
255.255.255.255 are reserved.   Windows is probably blocking that as a "favor".

Net Range	240.0.0.0 - 255.255.255.255
CIDR	240.0.0.0/4
Name	SPECIAL-IPV4-FUTURE-USE-IANA-RESERVED
Handle	NET-240-0-0-0-0
Parent	
Net Type	IANA Special Use
Origin AS	
Organization	Internet Assigned Numbers Authority (IANA)
Registration Date	
Last Updated	2013-08-30
Comments	Addresses starting with 240 or a higher number have not been allocated and should not be used, apart
from 255.255.255.255, which is used for "limited broadcast" on a local network.

This block was reserved by the IETF, the organization that develops Internet protocols, in the Standard document and in
RFC 1112. The documents can be found at:
http://datatracker.ietf.org/doc/rfc1112
RESTful Link	http://whois.arin.net/rest/net/NET-240-0-0-0-0
See Also	Related organization's POC records.
See Also	Related delegations.


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