Re: IPv6 in Debian
[I move this to the ipv6 list, I think this has little to do with
the -release list]
On Tue, Jul 31, 2007 at 12:29:37AM +0200, Tomas Pospisek wrote:
>
> I was trying to say that I had been bitten by the "libc's name resolver
> does by default an AAAA name lookup before it does an A lookup" before and
> am asking whether that's still a problem as [1] suggest that it was for
> Ubuntu at least until Dec 06 and whether someone can confirm it. As told I
> can not reproduce it on my systems any more since I removed ipv6 as soon as
> it started causing me trouble and as such cannot file a bug report against
> libc.
It still queries both AAAA and A records as soon as 1 ipv6 is
configured, which you'll always get for lo's ::1.
It appears this is not a problem for me because the nameserver I use
properly supports IPv6.
> You can not build systems that can deal with all and any unforseen
> fundamental chang in their environments.
>
> And arguably ipv6 is such a change (since it breaks applications). So
> arguing that applications don't "behave properly" or "behave wrong" is IMHO
> not correct. They break with ipv6 but not without. ipv6 is a new
> fundamental property of the system to deal with that came after the apps.
As far as I know, all applications that "break" are those that are
supposed to have ipv6 support, but the ipv6 support is broken.
It seems that some get a delay they shouldn't because of external
(to Debian) factors. This is most likely only a problem for people
who only have ipv4 connectivity. And we should do something about
that.
>> I've never actually had a problem on ipv4-only hosts. It would be nice
>> if you could describe your problems in more detail.
>
> The (concrete!) problems are described in the references I sent:
>
> [0] https://bugs.launchpad.net/ubuntu/+source/netcfg/+bug/24828
> [1] http://lists.debian.org/debian-devel/2000/12/msg01922.html
This seems to be about extra AAAA queries which seem to cause
delays for people with broken nameservers.
I think the rfc4472 referenced in the ubuntu bug report is something
we should get glibc to implement. It basicly suggests not do do AAAA
lookups in case you're not sure you have ipv6 connectivity. This
would basicly disable ipv6 by default, and atleast was the behaviour I
was expecting when you use AI_ADDRCONFIG.
> [2]
> http://www.google.com/search?q=dccproc+socket(UDP)%3A+Address+family+not+supported+by+protocol
Which just seems like a broken application.
Anyway, there are other type of applications that have a problem, and
that are those that fail to work if you disable ipv6 by disabling the
ipv6 module.
Kurt
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