While most of this is true there are some things to be cleared:josh wrote:... In your registrar there should be an option to "register nameservers" which actually adds your IP as the nameserver for your namespace, then you set up bind. Just like mail relaying tho a default bind install can be used by anyone as their DNS, so you'd probably want to harden the config so it only answers for domains you own
1) these nameservers are called "authoritative DNS servers" for your domain zone;
2) all of these servers will appear in the answer part when 'dig domain.tld NS' is queried;
3) your registrar must require that you have at least 2 different authoritative nameservers with IP addresses from 2 different IP subnets;
4) these nameservers are queried in a round robin fashion by clients;
5) because of 4) these server have to be synchronized and to respond with the same answer (or answer set when round robin fashion is used for multiple IPs per domain name) to a single query;
6) because of 5) usually master-slave DNS servers are used. Whether the response to a DNS query is received from the master or any of its slave servers doesn't matter.