[dns-operations] To A or to AAAA - was Re: Signaling client

[Mark Andrews]

In message <alpine.LSU.2.00.1101191342230.5244 at hermes-1.csi.cam.ac.uk>, Tony Finch writes:
> On Wed, 19 Jan 2011, Mark Andrews wrote:
> >
> > getaddrinfo() isn't the problem.  The problems happen after getaddrinfo.
> 
> Yes, you are right in principle.
> 
> I mentioned getaddrinfo itself because it also needs to be hardened
> against IPv6-related failures, specifically timeouts in AAAA lookups when
> A lookups succeed. If you can overlap the execution of getaddrinfo and the
> subsequent connect()s then you can connect to an IPv4 address
> quickly even if IPv6 is subject to either DNS or network level breakage or
> slowness.

99.999% of AAAA lookups work fine.  There are a few load balancers
which are broken or mis-configured, much less than there were 5
years ago.

> > I have slow start example code for all three of these methods which just
> > replaces the loop over the results of getaddrinfo().
> 
> Sounds nice! Is it published anywhere?

I intend to soon.

> Tony.
> -- 
> f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
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-- 
Mark Andrews, ISC
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