Hi Michael,

On 2012-12-14, at 11:59, Michael Thomas <m...@mtcc.com> wrote:

> Matthew Newton wrote:
>> On Fri, Dec 14, 2012 at 04:42:46PM +0000, Nick Hilliard wrote:
>>> On 13/12/2012 22:54, Jason Castonguay wrote:
>>>> Advisory — D-root is changing its IPv4 address on the 3rd of January.
>>> You've just given 3 weeks notice for a component change in one of the few
>>> critical part of the Internet's infrastructure, at a time when most
>> I think that /was/ the advance notification - you've got 6 months :)
>> "The old address will continue to work for at least six months
>>  after the transition, but will ultimately be retired from
>>  service."
> 
> So really stupid question, and hopefully it's just me, do I need to do 
> something
> on my servers?

When nameservers first boot, all they have is a hints file. This is either 
baked in to the software, or provided as a "hints file", or some combination. 
The hints file you have today will have the current/outgoing D-Root address.

The first thing a resolver does before it is ready for service, again, armed 
only with the hints file, is to send a priming query to a root server. This 
query is of the form ". IN NS?". Resolvers will try servers from the hints file 
until they get a response. Once the priming response is received, the data 
originally harvested from the hints file can be thrown away.

Once D-Root renumbers, a freshly booted resolver with an old hints file will 
either:

 - send a priming query to one of A, B, C, E, F, G, H, I, J, K, L, M, and 
obtain a response that contains the new D-Root address
 - send a priming query to the old D-Root v4 address, and also obtain a 
response that contains the new D-Root address

Once service is discontinued on the current/outgoing D-Root address, such a 
resolver might fail to obtain a response to its priming query if it happens to 
try the D/v4 address first. It will re-try with a different address until it 
succeeds. In principle, you only need one reachable address in the hints file 
to work to get up and running.

In summary, theory (and practice) tells us that:

1. You should update your hints file from time to time, and

2. If you don't, chances are overwhelmingly good that it will make no 
difference, and everything will work as normal.


Joe


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