Re: Teredo server selection

[Florian Weimer <fw@deneb.enyo.de>]

* Nathan Ward:

> On 23/12/2007, at 11:28 AM, Florian Weimer wrote:
>> * Nathan Ward:
>>
>>> 1) Lookup A record for `_teredo._udp.arpa.' (or whatever. Note the
>>> trailing . - we don't want to be looking up
>>> `_teredo._udp.arpa.defaultdomain' etc.)
>>
>> You should really discuss this with DNS people.  This is a very bad  
>> idea
>> because it produces lots of pointless queries which need to be handled
>> somewhere, probably on a production name server.

> You are talking about the use of .arpa, I assume, and query load on  
> the root servers?

Yes, but the issue will not be much different if you use any other zone.

> I think I understand the concern, but negative caching would deal with  
> this, same as it does for .local., .invalid., etc. The negative TTL on  
> both .arpa and . is 86400s.

This doesn't work too well in practice, unfortunately.

> We're only talking about 1 query each time the Teredo client boots, so  
> load on ISPs' recursive nameservers is not large - my laptop does  
> several queries per minute when idle, let alone at boot time or when  
> it's actively doing something.

Huh?  Why don't you have to requery when you suspect your network
environment has changed, or when you no longer can reach the Toredo
server (for an extended period of time)?