Re: [dnsext] Re: I-D ACTION:draft-vandergaast-edns-client-ip-00.txt

[Wilmer van der Gaast <[e-mail]>]

Hello Ted,

2010/1/28 Ted Hardie <[e-mail]>:
> The second motivation is to return different content based on geographic
> location and the likely implications for default language, character sets, and
> so on.  For that motivation, you want to associate the client with a server
> having that data as quickly as possible--without, for example, doing a
> 3xx redirect after reading the client's language preferences in their first
> request.
>
Our motivation is purely to improve the ability of authoritative
nameservers to send users to a nearby server. Although indeed the IP
address of the recursive resolver is often enough to do this, we've
seen several cases where it isn't. Think of ISPs with big networks
without setting up nameservers everywhere, or of open resolvers.

> Minimally, you'd seem to me to need to do something to figure out what
> an "external" value of an IP address for that host was when the
> resolver populated
> that field for hosts behind NATs.

The I-D specifically disallows exactly that. Resolvers behind NAT
should not need this option at all if they do the recursion
themselves, since the authoritative nameservers will find enough
accuracy in the packet source IP addresses already.

Most people simply don't run their own recursive resolver though.


Regards,

-- 
Wilmer van der Gaast, Dublin Traffic SRE.
Google Ireland.