Re: ai_flags in calls to getaddrinfo

[Robin Tarsiger]

Robin Tarsiger wrote:
> What happens if you pass nil for FAMILY but without the AI_V4MAPPED
> patch, on that system? Have you observed AI_V4MAPPED producing better
> results in any circumstance when you do not set FAMILY to ipv6?
> 
> I conjecture that your upstream resolver is blocking AAAA queries, and
> that AF_UNSPEC is going through a slightly different path, maybe even
> issuing an ANY query which is actually responded to with records from
> both address families, which are then passed through because response
> filtering and query filtering are different. If this is close to true,
> I'm not sure there's a sane way for an application to handle
> inconsistent resolver behavior of that stripe.

Aside:

Inconsistent caching resolver behavior often varies depending on the
state of the cache. So it is useful to try things like this two or
three times in a row in different orders, if you are not sure if
your DNS resolution chain is doing something dubious.

-RTT