DNS zone transfer is our main topic in this article. This is a Domain Name System term that you should know. What is its main purpose, and which are the different DNS zone transfers we will see today. Let’s begin.
DNS zone transfer – what does it mean
Zone transfer is the process of duplicating DNS information (DNS records) from the Primary DNS zone to the Secondary DNS zone. This enables you to create several copies of your DNS records on other name servers. If one of the name servers dies, you will have more availability as a result of completing the transfer. Furthermore, if you run a global website with users from all over the world and many presence locations, you will benefit from faster DNS resolution (PoPs).
Another important factor to note is that if a name server goes down for any reason, your website will not be damaged (for example, maintenance or a DDoS attack). It will stay accessible and available to your visitors.
If you administer a global website and want to speed up Domain Name System resolution, you might consider conducting a zone transfer to many Secondary zones. With this approach, you’ll be able to put your DNS data (DNS records) in numerous Points of Presence (PoP).
Types of DNS zone transfer
There are two main zone transfer types. They are as follows:
The first of these is “Full zone transfer.” AXFR zone transfer’s main purpose is to transfer all DNS records from the Primary DNS server to the Slave DNS server. As a result of the zone change, all DNS records will be updated. They’re the same as the ones in the Master DNS zone. When you deploy one or more Secondary DNS servers and want to replicate DNS records right away, you can use the AXFR zone transfer. If you know what I mean, one or more Secondary DNS servers haven’t been updated in a while. Then you have the option of forcing a full zone transfer.
Partial zone transfer, also known as IXFR transfer, is a method of transmitting only the most recent changes from the Primary DNS zone to the Secondary DNS zone. It is not essential to transfer the DNS data in its entirety. When only a few DNS entries have been changed, the IXFR comes in handy. For example, you’ve added two new A records while keeping the rest the same. Only the most recent data is available to the Secondary DNS server. If there is a variation in the serial numbers of the SOA record, it can be set to scan after a specific amount of time. If the serial number is lower, the changes will be requested and obtained from the Primary DNS server.
AXFR vs. IXFR
We could immediately tell the difference between the two types of zone transfer – partial zone transfer (IXFR) and full zone transfer (AXFR zone transfer) – when we compared them.
Duplicating the whole collection of accessible DNS records from the Primary DNS zone to the Secondary DNS zone is part of the full zone transfer. It’s often utilized when deploying a new name server or when the changes to the Secondary haven’t been updated in a long time.
When numerous Domain Name System records have been added, deleted, or updated, a partial zone transfer (IXFR) is utilized. The benefit is that you save bandwidth and don’t have to duplicate the complete zone file.
We can infer that zone transfer is a critical component of the whole Domain Name System. Therefore, if you want to make changes to it, you have to know it better.