How domain points to exact host?

Question

I know that when we put nameserver to domain it points to server then we put domain adress to a host so it basically connects each other. But lets say when I`m using AWS or other providers they give same Nameserver to everyone. If someone else puts my domain adress to his server by using same provider what happens ? There will be same nameservers for both of us.

Answer 1

The only name server that matters is the one listed by the registrar.

If there is a conflict at the name server level, then it is up to the policy of that service provider to sort out which record is valid.

I have not used AWS, but I know Rackspace only allows a given domain to be listed in one account.