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Bug#535833: marked as done (general: Slow internet on iceweasel, epiphany and so on...)



On Sun, Aug 02, 2009 at 08:39:46AM +0200, Tollef Fog Heen wrote:
> ]] Roger Leigh 
> 
> | Having working local networking is important.  We wouldn't consider
> | broken IPv4 loopback acceptable, and broken IPv6 loopback is just as
> | bad.
> 
> Sure, having it working is important.  Is it more important than keeping
> those (often new) users for whom Debian appears useless because of its
> perceived poor network performance?

It would be nice if both worked.  But, in the absence of good heuristics
for detecting broken networking, this is probably something that should
not be done automatically.

> Anyway, IIRC this is now solved in glibc by sending out the queries in
> parallel and returning the first answer you get.

OK.  What happens to the other answer(s) though?  Does this mean that
getaddrinfo(3) skips slow replies completely?  This is surely equally
broken if so?

For anyone with broken networking, the test program here:
http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=5;filename=addrtest.c;att=1;bug=441857
will test local name resolving in glibc; just replace ip6-localhost with
a hostname to check.

> | The idea behind the patch isn't bad, but the implementation proposed
> | here is too naïve.  The assumption that you only want working IPv6
> | name resolution when you have a globally-scoped IPv6 address is too
> | simplistic.
> 
> FWIW, it roughly matches what Mac OS X and Windows do.

And it's not considered broken on these platforms too?

I guess the proportion of IPv6 users is vastly lower on these platforms
due to the general networking clue level of the users, and that Windows
has had fully functional IPv6 networking for a much shorter time than
GNU/Linux.

> | Not only do you have the local loopback, you also have link-local
> | addresses which you can legitimately use.  Does zeroconf support
> | these?  Fundamentally breaking IPv6 for these use cases to work around
> | broken routing hardware is IMO a step too far.
> 
> Does anybody use IPv6-only link-local?

Probably not conciously; it's intended to be used automatically.  A
quick google shows Avahi does use these (with some caveats).

IPv6 has the concept of "Scope", and these scopes include Node/Host,
Link, Site, Organisation, and Global.  To assume that IPv6 networking
is only active when you have one or more Global addresses is an
incorrect assumption.  With the previous glibc patch, my networking
broke as the Global link went up and down.


Regards,
Roger

-- 
  .''`.  Roger Leigh
 : :' :  Debian GNU/Linux             http://people.debian.org/~rleigh/
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