First off, Dynamic DNS, also known as DDNS, is a service that will instantly update your IP address (the A or AAAA record) if the host (device) changes it.
When your IP address’s lease ends, your ISP (Internet service provider) can change it automatically.
You can use DDNS to ensure that the device will remain accessible if you utilize it as a server. Otherwise, you won’t be able to reach the new IP address or determine it from a distance.
Without Dynamic DNS, if you are operating a monitoring server with a camera at home and you have been viewing the video from a distance, the connection will break the instant the ISP changes the IP address, and you won’t be able to see anything.
So, do you want to be 100% sure that your domain is online? Backup DNS for your Primary DNS service is a handy addition that will make your DNS network broader. If you use a Backup DNS, you can add multiple nameservers that will be authoritative for your domain and answer queries.
Backup DNS service (Secondary DNS) is an additional DNS service that you can get from another DNS provider, different from your primary, with the goal to add extra redundancy. You can use extra nameservers as authoritative, and they can answer queries too.
The DNS is made up of numerous DNS zones. Moreover, the DNS server you’re using can better handle several zones to manage the DNS namespace. So, we can say that a DNS zone is a subset of the DNS namespace that a single administrator manages. It’s utilized as an organizational segment to provide you more control over DNS things like authoritative namespaces.
For your domain to function correctly, you must point it to various servers, including web servers, mail servers, etc. This is accomplished by adding multiple types of DNS records to the DNS zone. So, the DNS zone is where all Domain Name System records are stored. It is also the lone component responsible for the existence of the Domain Name System (DNS).