Re: v6ops-v6onbydefault: link-locals and AI_ADDRCONFIG

[Pekka Savola <pekkas@netcore.fi>]

On Wed, 29 Oct 2003, Juan Rodriguez Hervella wrote:
> I just say that this option is not *very* useful, having
> into account the problems that it has with link-local
> addresses and so on... if you fix these problems, it's
> a matter of choice, if you want to use it, just do it.

Which problems are you referring to?  I still don't understand :-(

> > > If I understood Stig well, he said that people was
> > > turning off IPv6 because of delaying issues. Doing that is not an option
> > > if you want to allow your app. to run over "IPv6 AND IPv4". If you can
> > > not cope with such delays, maybe you shouldn't be using the DNS at all.
> >
> > Then what?  Distributed hosts file? ;-) ?
> 
>  ^--^ ...(after a while)... pouting (grrrr).
> 
> Then what ? it's not my problem, 

Sorry for my remark, I just could not resist.  What you seemed to suggest 
was, "don't use DNS" without giving any reasonable alternative.  That 
isn't really productive either :-)

> I haven't switched to IPv4 because
> the IPv6 resolver took a couple of extra roundtrip times.

The extra roundtrip times are just the tip of the iceberg.  Consider 
broken DNS servers, load balancers etc. out there -- which may eat your 
AAAA query for e.g. 10 seconds, causing a lot more delay than a couple of 
roundtrips.

> I see another way of fixing:
> 
> If this option is problematic, don't use it. This has been proved to work,
> as a lot of applications don't use it already.

As for AI_ADDRCONFIG, it's maybe not used because it hasn't really been 
implemented that much, maybe because it has been specified in a rather 
useless way (and it requires a proprietary interface between the glibc and 
kernel to get the addresses, such as the getaddrinfo destination address 
ordering as well; dst addr ordering hasn't been implemented that much 
either)..

> You will have to give me other arguments to kill the on-link assuption.

Let's keep that subject to a separate thread, (the next message).

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings