This is something that I have regularly seen with cPanel servers, where if a 
local server is looking for www.example.com<http://www.example.com> and it sees 
that the cPanel DNS within that cluster contain a zone for example.com, it will 
not look any further as it considers it "authoritative", although it may not be.


Example: John Doe's website and domain registration for example.com is hosted 
with WebHost A on server1, and the DNS is with CloudFlare. The customer has 
correctly changed the nameserver records with WebHost A to point to CloudFlare 
(as you would expect one to). However, WebHost A is not aware that John has 
changed the nameservers over to CloudFlare and server1 still sees that there is 
a DNS zone for example.com on the DNS cluster. So server1 still thinks that the 
local DNS cluster is authoritative but everywhere else on the WWW see 
CloudFlare as authoritative.


CH.

________________________________
From: AusNOG <ausnog-boun...@lists.ausnog.net> on behalf of Peter Fern 
<aus...@0xc0dedbad.com>
Sent: Monday, 29 October 2018 3:05 PM
To: ausnog@lists.ausnog.net
Subject: Re: [AusNOG] Are domain name server pointers reliant on registrar name 
server?

This is indeed a confusing response.

Why does your nameserver have records for a domain it does not host?  If a user 
has delegated their DNS away to some other nameservers, you should not be 
serving any records from your nameservers, so the described scenario should 
never happen. Sounds like a problem for VentraIP to fix.

On 29/10/18 2:38 pm, Bradley Silverman wrote:
Hi Matt,

To answer your specific question, no they wouldn't.

BUT there is an exception:

If your site was hosting with us it does add one small layer of complexity, 
which often trips people up.
Servers are very arrogant, and assume they are the be all and end all. So for 
instance, let's say you are using Cloudflare as your Nameservers for 
example.com.au<http://example.com.au>, and your domain is with Synergy 
Wholesale.


Synergy Wholesale has the nameservers:
ns1.cloudflare.com<http://ns1.cloudflare.com> (I realize that is wrong)
ns2.cloudflare.com<http://ns2.cloudflare.com>

Cloudflare has the same nameservers plus:
An A record pointing to the VentraIP Server you are on 
(s111.syd2.hostingplatform.net.au<http://s111.syd2.hostingplatform.net.au>)
A MX record pointing to Outlook 365 for your email

VentraIP on S111.syd2 has the records:
An A record pointing to itself
A MX Record pointing to itself (the default for web hosting generally speaking).

In this circumstance, 
S111.syd2.hostingplatform.net.au<http://S111.syd2.hostingplatform.net.au> will 
assume it is the DNS host. The issue comes when your website has something like 
a contact form, or another user that uses VentraIP (and is on that server) 
tries to send an email, it will try to deliver locally.
This is where Remote MX (in cPanel) comes into play, it tells 
S111.syd2.hostingplatform.net.au<http://S111.syd2.hostingplatform.net.au> that 
it isn't the email host, and to send the email out into the world to find it's 
own way.

The other time this will get messy is if you have a sub domain defined on 
S111.syd2 for test.example.com.au<http://test.example.com.au> and also have an 
A record defined at Cloudflare pointing off to 
otherhostingcompany.com<http://otherhostingcompany.com>, the rest of the world 
will go to otherhostingcompany.com<http://otherhostingcompany.com> for the 
domain test.example.com.au<http://test.example.com.au>, but s111.syd2 will look 
at it's own subdomain for the site, only important in cases where your website 
at example.com.au<http://example.com.au> actually looks at 
test.example.com.au<http://test.example.com.au>.

I hope that answers it and doesn't make it more confusing for you!

[VentraIP Australia logo]

Bradley Silverman
Technical Operations \\ VentraIP Australia
M: +61 418 641 103 | P: +61 3 9013 8464 | 
ventraip.com.au<https://ventraip.com.au/>



On Mon, Oct 29, 2018 at 11:41 AM Matt Selbst 
<matt.j.sel...@gmail.com<mailto:matt.j.sel...@gmail.com>> wrote:
Hey Bradley,

Thanks for your answer. So assuming I'm not using you for DNS hosting (e.g. 
using a third party like CloudFlare or AWS Route53) then would your name 
servers ever be involved in DNS queries for my domain?

-Matt

On Mon, Oct 29, 2018 at 10:13 AM Bradley Silverman 
<bsilver...@staff.ventraip.com<mailto:bsilver...@staff.ventraip.com>> wrote:
Hi Matt,

A lot of confusing answers in here, even to me and this is my job to understand 
them.

To answer your exact question without filler information:
Your registrar (Synergy Wholesale, TPP Wholesale, NetRegistry) need to have the 
Nameserver records (ns1.server.net<http://ns1.server.net> and 
ns2.server.net<http://ns2.server.net>) for the domain 
(Example.com.au<http://Example.com.au>).
Then your actual nameservers (ns1.server.net<http://ns1.server.net> and 
ns2.server.net<http://ns2.server.net>) actually require the exact same 
nameserver records. Trust me, I have seen things go awry when this isn't the 
case.

While you are technically reliant on the root, auDA, and Affilias, all their 
job is to get someones request to the .com.au namespace TO the actual .com.au 
domains, and not something you ever have to worry about.

All you need to do is make sure both your registrar and your nameservers point 
to your nameservers. Does that make sense?
[VentraIP Australia logo]

Bradley Silverman
Technical Operations \\ VentraIP Australia
M: +61 418 641 103 | P: +61 3 9013 8464 | 
ventraip.com.au<https://ventraip.com.au/>



On Mon, Oct 29, 2018 at 6:16 AM Matt Selbst 
<matt.j.sel...@gmail.com<mailto:matt.j.sel...@gmail.com>> wrote:
Right, so for the sake of clarity as I understand it from the responses - I'm 
reliant on root, auDA and Afilias name servers but NOT my registrar e.g. 
Synergy Wholesale, TPP Wholesale, NetRegistry etc....

On Mon, Oct 29, 2018 at 5:59 AM Peter Fern 
<aus...@0xc0dedbad.com<mailto:aus...@0xc0dedbad.com>> wrote:
On 28/10/18 11:58 pm, Chad Kelly wrote:
> On 10/28/2018 11:10 PM, 
> ausnog-requ...@lists.ausnog.net<mailto:ausnog-requ...@lists.ausnog.net> wrote:
>
>> The original post was asking if the registrar is relied upon here
>> (and the answer is no).
> But the nameservers themselves still need to be listed at the
> registrar level so that they can be found on the public internet.
> Otherwise you run into issues with dns lookups and them not being able
> to resolve your dns correctly.
> They call this having registry hosts.
>

registrar != registry
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