Re: why I'm not implementing IPv6

[Pekka Savola <pekkas@netcore.fi>]

On Sat, 23 Nov 2002, Margaret Wasserman wrote:
> >IMO, it was a serious mistake to make the system libraries sort AAAA DNS
> >replies before A records (btw: I'm not aware of any implementation where
> >you could actually specify the order) when using getaddrinfo and
> >AF_UNSPEC.
> 
> Specifically, what problem does this cause?  

Applications which support v4 and v6 try to use v6 first when trying to 
contact dual-stack nodes.

> Are there many hosts
> that have IPv6 AAAA records in the DNS, but no connectivity via
> IPv6?

How many hosts are there that have IPv6 AAAA records in the DNS, but 
connectivity is *not* significantly worse than with IPv4?
 
> I don't believe in a "magic moment"...  In order for IPv6 to get
> deployed, we have to make dual stack nodes work properly throughout
> the transition AND build an IPv6 protocol and network architecture
> that has sufficient benefits for some situations, users and/or
> applications that it gets deployed and used.

I agree -- I had a different meaning for "magic moment" than djb.  To me 
it was the moment a site's operator feels confident enough to prefer v6 
connectivity to dual-stack nodes instead of v4.

Somewhere, this is today.  At production networks, I don't feel it's time 
for that yet.

> >If this would have been different, we migh have a significantly higher
> >number of v6-enabled applications etc. enabled in the mainstream
> >distributions.
> 
> How would specifying a different order for DNS records achieve
> this?

People could deploy v6-enabled applications and enable v6 by default on 
their boxes without a fear of it interfering with v4.  That'd be a *huge* 
benefit.

I've already expressed my fear about this, see e.g.
http://staff.csc.fi/psavola/residential.html
"Migration and Co-existence Scenarios" section.

That section would have been entirely different if the sort order had been 
reversed.

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords