On Thu, 27 Aug 2015, Alan Cronin (alcronin) wrote:

Howdy! Sorry for responding so slowly.

> The change involves adding an option to Curl (something like
> CURLOPT_IP_FAMILY_PREFERENCE) which would allow a preference of IPv4 vs IPv6
> to be set for the first connection in a dual stack environment. This
> functionality would extend the happy eyeballs algorithm.
>
> There is already an CURLOPT_IPRESOLVE option which limits the IP version but
> this new option is more a preference in the case there is both an IPv4 and
> IPv6 interface for the connection.
>
> We propose making a change to connect.c::Curl_connecthost() and reorder the
> conn->tempaddr object before calling singleipconnect() based on the option
> set by the consumer.
>
> What are your thoughts on this proposal?

I'm not opposed adding an option like this, but still, can you tell us
something about the motivation/need for this so that we understand it better?
Happy Eyeballs is after all explicitly designed to slightly favor IPv6.

-- 
  / daniel.haxx.se
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