Re: Geographic map of IPv6 availability

On 15/10/2007, at 8:24 PM, Martin Hannigan wrote:

> [moresnip]
>
> The way I read the portion of the thread related to
resolver behavoir
> was that the resolver behavior was being discussed. Not
the client.
> The resolver should have an attribute to select the
preference between
> A vs. AAAA. Otherwise, it's setting network policy
through code.
>
> My question was if there is an option to adjust this,
where is it? I
> don't see it. I'm not a BIND uber-expert. If there is
no option, there
> quite possibly ought to be one.

I guess the question could also be asked as to whether BIND
honours  
the host's configuration of the address selection policy -
which  
seems more likely than implementing it itself.

For those who missed it - OS level address selection policy
won't  
apply to BIND without specific code, as BIND is a recursive
resolver  
so won't be calling getaddrinfo(3).

--
Nathan Ward

On 15-okt-2007, at 11:50, Nathan Ward wrote:

>> The way I read the portion of the thread related to
resolver behavoir
>> was that the resolver behavior was being discussed.
Not the client.
>> The resolver should have an attribute to select the
preference  
>> between
>> A vs. AAAA. Otherwise, it's setting network policy
through code.

How is using an address that is present "setting
network policy"?

> For those who missed it - OS level address selection
policy won't  
> apply to BIND without specific code, as BIND is a
recursive  
> resolver so won't be calling getaddrinfo(3).

(I missed that we were talking about BIND in my previous
message, by  
the way. Sorry.)

Some quick experimentation suggests that BIND ignores the
policy  
table and just round robins (or something that looks like
it) through  
all available addresses. Try some different non-existing
hostnames  
under kame.net, which has two NS records that both have an
IPv4  
address and one has one IPv6 address and the other one has
two.

On 10/15/07, Mark Andrews <Mark_Andrewsisc.org> wrote:
>
> In article <ECD70626-8EB0-4651-8A3E-51D783571389daork.net> you write:
> >
> >
> >On 15/10/2007, at 8:24 PM, Martin Hannigan wrote:
> >
> >> [moresnip]
> >>
> >> The way I read the portion of the thread
related to resolver behavoir
> >> was that the resolver behavior was being
discussed. Not the client.
> >> The resolver should have an attribute to
select the preference between
> >> A vs. AAAA. Otherwise, it's setting network
policy through code.
> >>
> >> My question was if there is an option to
adjust this, where is it? I
> >> don't see it. I'm not a BIND uber-expert. If
there is no option, there
> >> quite possibly ought to be one.
> >
> >I guess the question could also be asked as to
whether BIND honours
> >the host's configuration of the address selection
policy - which
> >seems more likely than implementing it itself.
> >
> >For those who missed it - OS level address
selection policy won't
> >apply to BIND without specific code, as BIND is a
recursive resolver
> >so won't be calling getaddrinfo(3).
> >
> >--
> >Nathan Ward
>
> named actually measures the response times to
individual addresses
> and uses those to determine which servers to query. 
Named also
> uses what addresses it has before attempting to
determine if there
> are alternate addresses.
>
> Address selection policies are kind of meaningless in
this environment.

How so? I think it's valuable to be able to decide for
myself if I
want preference for AAAA or A. If I understand what I am
reading, and
am properly recalling past threads here, this would seem
important
since it affects the user experience.

As far as how it sets network policy goes, any time
something sets a
preferred mode over other options and is not modifiable,
it's akin to
setting policy. History has shown that most of us agree with
this.

If I'm not interpreting this correctly, I'm all ears
(eyes).

[ Note, I'm not making any assumption that anyone has set
out to set
internet policy through software. ]



-M<