A ways back, I'd set up nameservers on my VPS (let's call them 'ns1.mydomain.com' and 'ns2.mydomain.com'). I host a couple of dozens websites on that VPS.
For all of my domains, on the domain registrar's site, I'd set the Nameservers for that domain to Custom Nameservers: 'ns1.mydomain.com' and 'ns2.mydomain.com'.
Recently, I had to ask my VPS provider to create a new server for me (let's call it 'newVPS'), leaving my previous VPS (let's call it 'oldVPS') active so I could migrate or re-create accounts and contents from the oldVPS to the newVPS.
Both the oldVPS and newVPS use WHM/CPanel admin interfaces.
The oldVPS is setup as (cut and pasted from the WHM panel banner): 'CENTOS 6.9 i686 virtuozzo – oldvps WHM 56.0 (build 52)'
The newVPS is setup as (cut and pasted from the WHM panel banner): 'CENTOS 7.4 virtuozzo [newvps] v68.0.21'
My understanding (which is limited in these areas) is that the nameservers I setup on my VPS have to be associated with one of the domains I own/host on that VPS.
The nameservers which I had previously setup on oldVPS were associated with 'mydomain.com' one of the domains/accounts hosted on oldVPS.
For simplicity, I'm thinking of creating new nameservers on newVPS and associate them with 'myotherdomain.com', another domain/account to be hosted on newVPS.
How do I create my new nameservers on newVPS, say 'ns1.myotherdomain.com' and 'ns2.myotherdomain.com', presumably from newVPS's WHM (I'm guessing under one of the DNS Functions but not sure which one, e.g. 'Add a DNS Zone', or 'Add an A entry for your Hostname', etc.)?
The problem i'm having is that after I add an A entry for the root account on my VPS it reverts back to the IP address it had on the old server. I've tried to assign different namerservers on the old server thinking that it was overiding the IP addresses I was setting on the new server but to no avail.