DNS (Domain Name System) is an integral part of the internet infrastructure that is responsible for translating human-readable domain names into machine-readable IP addresses. DNS lookups occur each time a user visits a website, as the browser has to contact the DNS server to find the IP address associated with the domain name. While DNS lookups are necessary for website access, they can also cause performance issues, particularly when a website requires a large number of DNS lookups to load. In this article, we will discuss how to reduce DNS lookups to optimize website performance.

What are DNS Lookups?

DNS lookups are the process by which a web browser or other network client queries a DNS server to obtain the IP address associated with a specific domain name. Every time a user visits a website, the browser sends a DNS lookup request to the DNS server to find the IP address associated with the domain name. This is necessary because domain names, such as www.example.com, are easier for humans to remember than IP addresses, such as

DNS lookups can have a significant impact on website performance. Each DNS lookup takes time, and if a website requires many DNS lookups, the user may experience a delay in accessing the website. Additionally, if the DNS server is slow or unresponsive, the user may not be able to access the website at all.

How to Reduce DNS Lookups:

There are several ways to reduce DNS lookups and improve website performance. In this section, we will discuss some of the most effective methods.

  1. Reduce the Number of Hostnames:

Each hostname on a webpage requires a separate DNS lookup. Therefore, reducing the number of hostnames can help to reduce the number of DNS lookups required to load a webpage. To achieve this, website owners can consolidate resources, such as images, scripts, and stylesheets, into a single hostname. This is also known as domain sharding.

Domain sharding is the process of splitting resources across multiple subdomains to increase the number of parallel downloads that a browser can perform. For example, a website that has several images, scripts, and stylesheets can be split into several subdomains, such as img.example.com, js.example.com, and css.example.com. This allows the browser to download resources from each subdomain simultaneously, improving website performance.

However, it is essential to note that domain sharding can also increase the number of DNS lookups required to load a webpage. Therefore, it is important to strike a balance between reducing the number of hostnames and minimizing the number of DNS lookups required.

  1. Use DNS Caching:

DNS caching is the process of storing DNS information locally on the user’s device or in a proxy server. By caching DNS information, the browser or proxy server can avoid performing additional DNS lookups for a specific period. This can significantly reduce the time required to load a webpage.

DNS caching can be done at different levels, such as the browser level, the operating system level, or the proxy server level. Most modern browsers, such as Google Chrome, Firefox, and Safari, have built-in DNS caching. However, the duration of the caching may vary depending on the browser and the operating system.

  1. Use a Content Delivery Network (CDN):

A content delivery network (CDN) is a network of servers located in different geographical locations that work together to deliver content to users. CDNs can help to reduce DNS lookups by caching content, such as images, scripts, and stylesheets, on multiple servers worldwide. When a user requests content from a website, the CDN delivers the content from the server located closest to the user, reducing the distance the content has to travel.

How to Reduce DNS Lookups: Now that we understand what DNS lookups are let’s look at how to reduce them for better website performance.

  1. Use DNS Prefetching:

DNS prefetching is a technique that allows a browser to perform a DNS lookup in advance, before the user clicks on a link. This can help reduce the time taken for DNS lookups, as the lookup is performed before the user needs to access the resource.

To implement DNS prefetching, add the following HTML code to your website’s header:

bashCopy code<link rel="dns-prefetch" href="//example.com">

Replace example.com with your website’s domain name.

  1. Use HTTP/2:

HTTP/2 is the latest version of the HTTP protocol that supports multiplexing, which allows multiple requests to be sent over a single connection. This can significantly reduce the number of DNS lookups and improve website performance by reducing the connection overhead.

  1. Reduce TTL:

TTL (Time to Live) is the amount of time a DNS record is stored in the cache before it expires. By reducing TTL, the DNS resolver will check for new DNS records more frequently, reducing the need for DNS lookups and improving website performance.

  1. Use Google’s Public DNS:

Google’s Public DNS is a free DNS resolution service that can significantly improve website performance by reducing DNS lookup time. Google’s Public DNS has a large global network, making it faster and more reliable than many other DNS resolvers.


It is crucial to keep track of and minimize DNS lookups for better website performance. The availability of various third-party services makes it effortless to accumulate a significant number of external requests that can cause significant delays for website visitors.

To improve website speed and efficiency, one can use a CDN, minimize external resources, enable DNS prefetching, reduce the TTL of DNS records, choose a DNS provider with a global network, and eliminate unused DNS records.

Regularly reviewing DNS configuration is also essential to ensure that it is up-to-date and accurately configured. By implementing these measures, one can enhance website performance and deliver an improved user experience for visitors.