[181233] in North American Network Operators' Group
Re: Anycast provider for SMTP?
daemon@ATHENA.MIT.EDU (Joe Abley)
Fri Jun 19 09:42:15 2015
X-Original-To: nanog@nanog.org
From: "Joe Abley" <jabley@hopcount.ca>
To: "Christopher Morrow" <morrowc.lists@gmail.com>
Date: Fri, 19 Jun 2015 09:42:09 -0400
In-Reply-To: <CAL9jLaamSUeNf7QyumC3PYgZK-w5FcXERbkGcEs6p52EuuDW_A@mail.gmail.com>
Cc: NANOG list <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
On 19 Jun 2015, at 8:12, Christopher Morrow wrote:
> On Fri, Jun 19, 2015 at 7:19 AM, James Hartig <fastest963@gmail.com>
> wrote:
>
>> Just curious, how does DNS load balancing work if people are using
>> 8.8.8.8/208.67.222.222 or basically any public resolvers that cache
>> and
If the client that performs the upstream query within the
8.8.8.8/whatever infrastructure is close to you for some meaningful
interpretation of "close" then you still get an answer that is
(effectively) localised for you.
If the resolver infrastructure is sufficiently far that what is good for
it is not good for you, then the deployed (if not quite standardised)
answer is edns-client-subnet: the resolver infrastructure you're using
embeds your client address in its upstream query. The authority servers
can then localise a response (and scope it) as being suitable for you,
not the resolver in general.
http://tools.ietf.org/html/draft-vandergaast-edns-client-subnet-02
There are privacy concerns, here. But we might posit that you've already
in the business of trading privacy for convenience if you're using a
public resolver.
> don't know exactly, but you might get some interesting clues from the
> f-root or as112 designs, eh?
Root servers and AS112 servers don't steer clients towards content
according to where they are. They give consistent answers for all
queries, regardless of where they came from.
Joe
