Re: [mif] [dnsext] [DNSOP] 2nd Last Call for MIF DNS server selection document

[Keith Moore <[e-mail]>]

On Oct 24, 2011, at 4:52 PM, Doug Barton wrote:

> On 10/24/2011 05:16, Keith Moore wrote:
>> That's the point - search lists are not appropriate most of the time, and it's very hard for software to distinguish the cases where they are potentially appropriate from the cases when they're not, and it's not possible for software to do this in all cases.
> 
> There's been something missing from this discussion, and I finally put
> my finger on it. TMK most stub resolvers have an option similar to this
> one from ISC's:
> 
> ndots:n
>        sets a threshold for the number of dots which
>        must appear in a name given to res_query() (see
>        resolver(3)) before an initial absolute query
>        will be made.  The default for n is “1”, mean‐
>        ing that if there are any dots in a name, the
>        name will be tried first as an absolute name
>        before any search list elements are appended to
>        it.
> 
> So it seems that this question is already a matter of local policy,
> which given the number and quality of the divergent views seems
> eminently reasonable. Can we move on now?

No, because relying on "local policy" is not sufficient for interoperability.

I think there's a need for IETF to document why any other value than 1 is a Bad Idea, and more to the point, why it will break things.    The problem isn't entirely specific to hosts with multiple interfaces.  But given that using multiple interfaces makes the problem worse, MIF might want to take on some of the work of documenting why it will break things.

Keith