Firefox 3 Beta 2 in Rawhide

Daniel P. Berrange berrange at redhat.com
Sun Dec 23 21:17:17 UTC 2007


On Sun, Dec 23, 2007 at 12:28:37PM -0700, Richi Plana wrote:
> On Sun, 2007-12-23 at 10:51 -0800, Andrew Farris wrote:
> > The correct fix is to make firefox fallback on IPv4 if an IPv6 address fails
> > (and yes I know that is more work).  In the meantime if it has an option to
> > 'prefer IPv4' even if IPv6 is configured that might be fine, but I really don't
> > think disabling it is a good option.
> > 
> > We still probably should not be enabling the IPv6 address unless requested by
> > the users (for which there is a very obvious UI option already right in the
> > network configuration), but that is a broader discussion that has happened a few
> > times before.
> 
> A better fix (and one that other subsystems could use) is a program that
> detects whether IPv6 will be a problem for the user and set a flag
> somewhere global that programs can check or scripts can recognize and
> thus set the defaults for programs like FF to enable or disable IPv6.
> Cascade effect from a global config to a minor. After all, if IPv6 isn't
> enabled in the Network layer, then applications shouldn't either.
> 
> It's an ugly solution for an ugly situation.
> 
> As for not enabling IPv6 by default, you'll find by going back through
> fedora-devel archives that you'll find just as many IPv6 proponents for
> the sake of enabling new technologies as you'll find anti-IPv6 for the
> sake of security/not-installing-unneeded-functionality/etc. Can o' worms
> for you.

There is no technical reason why we should have to choose between enabling
and disabling IPv6  in firefox. If it correctly follows the RFC 3484 for 
DNS resolution then it would 'just work'. Applications which are correctly
written will use 'getaddrinfo' to resolve names. This will automatically
decide whether to return IPv4 addrs, or IPv6 addrs or both, and will sort
them in the order most likely to succeed.   If you have only link-local
IPv6 addresses (which all Fedora installs do by default) then it will
*not* give you back IPv6 addrs since you can't reach them. Likewise if you
have a site-local IPv6 address, it will not give you back IPv6 addrs that 
are out on the internet because they would not be routable. There's all 
sorts of rules on prioritization, but the effect is IPv4 & IPv6 will always
be enable in the DNS lookup and apps should 'just work' whatever interface
address config they have.

  http://people.redhat.com/drepper/userapi-ipv6.html
  http://www.rfc-editor.org/rfc/rfc3484.txt

Dan.
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