What is DNS cache and how does it work?

You’ve come to the right place if you’re looking for an explanation of DNS cache. In this article, we’ll take a closer look at its purpose, as well as its function and benefits.

DNS cache purpose

DNS cache memory is a type of temporary cache memory used by DNS resolvers and other devices. Initially applied DNS records of searched domain names are retained in that memory. These records contain the domain names’ IP addresses (IPv4 or IPv6), as well as information about their email server, information about their services, authentication and verification data, and more. The DNS cache will save all of the data. However, as aforementioned, it will only be for a limited period of time, as set by the TTL (Time to Live) number assigned to each DNS record.

How does it work?

It works in a straightforward manner. When a user requests a domain name, a DNS query is initiated. The user’s device will then check its DNS cache, which is incorporated into its operating system (OS). It’s a database that keeps track of different DNS records and their TTL values. As previously indicated, the DNS administrator for the domain sets the TTL. If the TTL hasn’t elapsed, the required DNS records can be discovered immediately. The request will be processed, and the domain will load promptly. If the TTL has already gone, a new lookup will take longer because the entire process will have to be repeated.

This signifies that a DNS recursive server will accept the user’s request and ask other servers for DNS records. It will first ask the root server, which will direct it to the specific TLD server to be searched, and then the recursive will be forwarded to the authoritative name server, which will finally provide DNS data (records).

The information will be sent to the user’s browser, which will then load the domain. These files will be cached in the Domain Name System cache of the recursive server, and the user’s device (computer, tablet, or mobile) will have access to them for as long as their TTLs permit.

Benefits of DNS cache

  • DNS Cache stores DNS responses to protect your authoritative DNS servers from DDoS attacks and reduce the load on your authoritative DNS servers.
  • It allows you to connect to the nearest node, which accelerates availability.
  • If you have an on-premises Domain Name System, DNS Cache can help you save money by lowering bandwidth usage.
  • Furthermore, you can use the service if an error in authoritative domain names happens before the cached DNS records expire. This reduces the amount of time lost due to failures.


The DNS cache is an effective instrument for speeding up and streamlining the DNS resolution process. It saves the network (the several servers involved) and the user’s device time, effort, and resources.

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