What happens if DNS is changed

It’s likely that users are sending recursive DNS queries to your website when they visit it.

So what is the operation of recursive DNS servers?

Let’s look at an example of what happens when you request an IP address (A record) for github.com from a recursive DNS server, such as

Hurray! For github.com, we have an A record! The IP address of github.com is now in the hands of the recursive nameserver, which can provide it to you.

There are two primary options available when updating your DNS records:

  • Full Zone Transfer (AXFR): This option allows you to transfer the entire zone file from one DNS server to another. It is typically used when you are migrating your DNS to a new server or when you need to synchronize DNS records between multiple servers.

  • Incremental Zone Transfer (IXFR): This option allows you to transfer only the changes made to the zone file since the last transfer. It is more efficient than a full zone transfer and is commonly used for regular updates to DNS records.

But we’ve overlooked something crucial! ITTs!

With such a short TTL, everyone should in theory receive the new IP address for github.com within 60 seconds if Github decides to change the IP address for github.com and their DNS implementation follows the DNS standard.

Initially, I changed the DNS record on my nameservers (Cloudflare) to an A record mapping test.jvns.ca to

This functioned right away! Since there was no test.jvns.ca DNS record that could have been cached earlier, there was absolutely no need to wait.

What would happen if we attempted to modify that IP address? After making the change to, I performed the same DNS query.

Not all things adhere to the DNS specification, as is the case with most internet protocols.

My registrar was stating "THIS WILL TAKE 48 HOURS" because NS record TTLs, which determine which nameserver recursive nameservers should contact, are MUCH longer!

The.com nameserver receives a new NS record with the new domain when I update the nameservers for examplecat.com.

Another reason why TTLs might not be honored in practice is that a lot of programs have to resolve DNS names, and some of them keep DNS records in memory indefinitely (until they are restarted).

Now let’s explore whether is still the fastest DNS. is designed to be the fastest DNS directory on the Internet.

The fastest DNS service in the world is, according to independent DNS monitor DNSPerf.

It takes two minutes to set up and doesn’t require any specialized software or technical knowledge.

There are now more and faster private DNS servers on your device. is an alliance between APNIC and Cloudflare.

One of the biggest, fastest networks in the world is operated by Cloudflare.

No, Cloudflare plans to continue offering the DNS service in the near future because it firmly believes in the benefits of free, quick, and private DNS.

Now let’s see if changing the DNS settings is acceptable.

You can improve your security, privacy, and speed (by a few milliseconds, but why not?) by changing your default DNS server.

The majority of ISPs don’t provide phishing defense. Additionally, they usually don’t use DNSSEC or DNSCrypt, which are security features that guard against eavesdropping, hijacking, and redirecting your DNS requests.

Changing your DNS can assist if you need to get around geoblocking or an ISP block on a particular website.

You probably won’t gain more than a few fractions of a second in faster load times by switching, unless your DNS is extremely slow.

Overall, you have nothing to lose by quickly switching, and it’s not nearly as technically challenging as it sounds.