[ntp:questions] Pool returns IPv6 address to IPv4 query

Rick Jones rick.jones2 at hp.com
Tue Nov 19 17:33:29 UTC 2013

Danny Mayer <mayer at ntp.org> wrote:
> That must have been a short discussion. getaddrinfo() has nothing to
> do with the IP stack. getaddrinfo()'s job is to get information from
> the nameservers you specify in resolv.conf or wherever else the OS
> has that information. Its job is NOT to make decisions about what it
> should ask for. That's the programmer's job when setting up the API
> call as to what addresses to ask for.

I suspect it all boils down to the behaviour when one sets
AI_ADDRCONFIG in the getaddrinfo() call.  When that is set, ostensibly
getaddrinfo() is supposed to filter-out any reponses that are of a
type that cannot be used by the application.  The decision made was if
there were no non-loopback-interface IPv6 addresses configured, AAAA
records would not be returned from the getaddrinfo() call.  Similarly
for A recorecords if there were no IPv4 addresses configured on the

Later, when interfaces started getting auto-configured, local scope
IPv6 addresses, there was a call to change that to be "don't return
IPv6 addresses unless there is a better-than-local-scope IPv6 address
assigned."  Started causing me all manner of pain in netperf :( Not
sure where that stands now in the Linux world.

rick jones
oxymoron n, Hummer H2 with California Save Our Coasts and Oceans plates
these opinions are mine, all mine; HP might not want them anyway... :)
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