Nameserver host records and NS records

[faris]

I'm embarrased to ask this, because I should really know this stuff. In fact I thought I did. But I think I've confused myself.

Background:
Server A: Plesk box, primary DNS, ns1.mydomain.com, ip=1.1.1.1

Server B: secondary dns (via 4PSA's excellent DNS Manager), ns2.mydomain.com, ip=2.2.2.2


Problem:
I'm going to be moving to a different co-lo company, and will be assigned new IPs for both Server A and Server B (call them 3.3.3.3 and 4.4.4.4).

What I've decided to do is move dns completely off both of those machines and onto two separate ones running locally (which are not moving anywhere) so that when the time comes to change IPs on the servers, I can be ready and waiting and able to manually modify records whenever I want, very easily etc without Plesk getting in the way. For the sake of this discussion, we'll say the two local machines have IPs of 11.11.11.11 and 22.22.22.22)

So I thought "no problem". All I do is set up the new machines, duplicate the dns records from the existing machines, then change the nameserver host record IP addresses associated with ns1.mydomain.com and ns2.mydomain.com to 11.11.11.11 and 22.22.22.22 via my resgistrar.

But now comes the crucial and confusing bit. In the DNS settings for mydomain.com, I currently have NS records for ns1.mydomain.com and ns2.mydomain.com pointing to 1.1.1.1 and 2.2.2.2

Where in the heck do these come into the equation? You tell your registrar which namservers that should be associated with a domain (as an "URL"). So this needs to be translated to an IP. Now if there are namserver host records registered somewhere, shouldn't these be looked up rather than any NS records in a domain's DNS config? If not, then maybe I'm asking the wrong question. Should I be asking why it is necessary to "create" nameserver host records via a registrar when a domain has NS records?

Either way, what is the best order to make changes to things? the NS records in the DNS for mydomain.com first, then change the IPs via my domain name registrar? Or the other way around?

And what happens in the meantime? I mean the changes made via the registrar will propagate differently to the changes I'll make to the DNS for the domain, so something somewhere is going to see that ns1.mydomain.com points to 1.1.1.1 but will then find that ns1.mydomain.com has an NS record pointing to 11.11.11.11 (or the other way around). What sort of problems is this likely to cause me?

Thanks,

Faris.

 

[jamesyeeoc]

But now comes the crucial and confusing bit. In the DNS settings for mydomain.com, I currently have NS records for ns1.mydomain.com and ns2.mydomain.com pointing to 1.1.1.1 and 2.2.2.2

Since you are changing the IP's for your ns1/ns2 servers, you will have to change the IPs in the DNS settings for all domains which have A records pointing to the old nameserver IPs.

Now if there are namserver host records registered somewhere, shouldn't these be looked up rather than any NS records in a domain's DNS config?

The registrar nameserver entries are what tell the requester/resolver what IP to go to to actually get the record information.

Windows workstation sends a request out. The top level gTLDs respond by giving your ns.yourdomain.com IP, the request is then given to your ns.yourdomain.com, and hopefully the record (A, MX, whatever) is given back. (This is a simplistic nutshell explanation)

 

[faris]

Right. That makes sense. So ...

lookup->root-server->my-nameserver->Domain-DNS->Domain-NS

...with the root servers being told the correct namserver via the doman's host records (as set via the registry).

Thanks. I'm "un-confused" now.

Faris.