I understand the concept of what needs to be done, but I'm not entirely sure about the technical implementation in ISP panels (which, honestly, are the most frustrating panels to work with.

Here's the situation:

You have 2 VPS, each with 3 IPv4 addresses and their own ISP.

The idea is to attach the main domain to one VPS (let's say domain.com) and create child DNS on it: ns1.domain.com, ns2.domain.com, ns3.domain.com.

On the second VPS, you want to host sites that will work on your NS.

It sounds like you're on the right track. You've created manual entries on the first VPS, and the main domain has been successfully updated to point to its own NS.

Now, the question is: How do you make other domains on the second VPS work on your NS that are sitting on the first VPS?

Or is it impossible in this case?

To achieve this, you can utilize a combination of DNS delegation and synchronization across the VPS servers. Here's how you can technically implement this in the ISP panels of the VPS servers:

1. Configure DNS Delegation:
  - Access the ISP panel of the first VPS and set up NS (nameserver) records for ns1.domain.com, ns2.domain.com, and ns3.domain.com, pointing to the IP addresses of the second VPS. This delegation establishes that the second VPS will have authority over the DNS records for the child domains.

2. Secondary DNS Configuration:
  - On the second VPS, install and configure a DNS server software such as BIND or PowerDNS. Configure this server to act as a secondary (or slave) DNS server for the main domain hosted on the first VPS. This involves setting up zone transfer settings to automatically synchronize DNS records from the first VPS to the second VPS.

3. Domain Hosting:
  - When hosting a new domain on the second VPS, ensure that the domain's DNS records point to the nameservers ns1.domain.com, ns2.domain.com, and ns3.domain.com. Update the registrar settings for the new domain to use these custom nameservers, delegating the DNS resolution responsibility to the second VPS.

4. Testing and Validation:
  - Perform thorough testing to verify the functionality of the distributed DNS setup. This includes testing domain resolution for the child domains hosted on the second VPS, ensuring that changes made to the main domain's DNS records on the first VPS are synchronized to the second VPS, and validating the effectiveness of TTL (Time to Live) settings for DNS caching.

Additionally, consider implementing automated monitoring and alerting systems to promptly address any potential DNS synchronization issues between the VPS servers.

When working with a gTLD, it is crucial to have the name servers of the first domain registered with the domain registrar. This can be accomplished by inquiring with the domain registrar about the correct name servers to use.

In the case of a COM domain, it is necessary to seek guidance from the domain registrar regarding the appropriate name servers. This step is vital in ensuring the proper configuration and accessibility of the domain on the web.

The first step is to perform the following tasks:

1. Combine all VPSs into a DNS cluster consisting of three VPSs with three different IP addresses and three DNS servers. In ISP manager, there is an option to connect another VPS based on ISPMGR for DNS records.

2. Initiate synchronization with the handles.

3. Change the DNS for the domains.

It may also be necessary to make adjustments to the domain zone.

If all three virtual machines are on the same dedicated server, then if the dedicated server goes down, all nameservers will also go down.

This implies significant negative consequences due to DNS caching, as it could take up to 10 minutes for the cache to update, potentially resulting in lost visitors over the next eight hours.

I haven't used this panel for a long time, so I might not be able to provide more detailed advice.