Azure DNS Time response

Question

We have a application hosted on top of compute instance Azure Cloud. The DNS Query seems to be quite Slow. Can we check somehow why the response is so slow and whether there is some caching at the OS Level.

Answer 1

The reason behind the Azure DNS slow response maybe due to below:

• When you create new DNS zones and DNS records in the Azure DNS name servers they will appear quickly in few seconds.
• When you are trying to modify existing DNS records this may take a little longer.
• It may take up to 60 seconds to reflect in Azure DNS name servers.
• As you mentioned, 'DNS caching by DNS clients and DNS recursive resolvers outside of Azure DNS also can affect timing.'
• Use Time-To-Live (TTL) property to manage cache duration for the record set.
• Time-To-Live (TTL) represents how long each record is cached by clients before being re-queried.
• TTL value ranges between 1 and 2,147,483,647 seconds.

For more in detail, please refer the below links:

https://docs.microsoft.com/en-us/azure/dns/dns-faq#how-long-does-it-take-for-dns-changes-to-take-effect-

https://docs.microsoft.com/en-us/azure/dns/dns-zones-records#time-to-live