Test your DNS server’s speed/response time

A DNS server (Domain Name Server) will translate a fully qualified domain name (FQDN) to an IP address. In short, if you go to google.com, this request will first be sent to a DNS server. This DNS server will check the IP address which corresponds with this FQDN and will sent back a reply: the IP address of the server which hosts this website.

It is important to have a fast and reliable DNS servers set up for your device as you will probably visit hundreds of websites on a daily basis or even more. So each time you visit a website, your browser or the application you use will have to lookup a domain name’s IP address. So you want this process to be quick and without any errors.

Step 1 – Download Namebench

Namebench is a little tool which will allow you to test a ton of nameservers. This tool is available for Linux, Mac OS X and Windows. You can download the tool from here.

Step 2 – Start the benchmarking of your DNS server(s)

Often, your DNS servers are defined within your router. It is also possible you defined your nameservers on the device you are using. In case these DNS servers are defined in your router’s configuration, the nameserver that should be displayed is or the private IP address of your router.

namebench main program window

Now you can define the query data source. You will be probably be fine if you just choose ‘Top 2,000 Websites (Alexa)’. This means that the top 2,000 most visited websites’ will be resolved to their IP addresses. The tool will benchmark how long it takes for each of the DNS servers tested to get the IP address. Click on ‘Start benchmark’ and sit back for a few minutes so the tool can start its benchmarking!

Step 3 – Analyse the results

Your third step is to analyse the results. Once Namebench has finished its testing (it should take no more than 10 minutes – this depends on the query data source and your internet connection), a webpage with the results should open. This is a simple HTML page which is stored locally and will display the results of the DNS benchmarking.

The recommended configuration is displayed in the top right corner. If you are in a hurry, go to step 4 to set these new nameservers as your default.

Recommended DNS configuration

Cool! So Namebench has now automatically determined which three nameservers are the fastest and nearest and thus the recommended nameservers for your internet connection. It should be good to also check the graphs displayed below this result, such as the mean response duration or the response distribution chart for the first 200ms.

Mean Response Rate


Response Distribution Chart


Step 4 – Set your new DNS server(s)

It is common for ISPs to have their proper DNS servers for their customers. These DNS servers are often based close to the customer and provide a low response rate and is reliable enough. If this is the case, you probably don’t have to change your DNS servers at all and you already have fast nameservers.

But in case your current DNS servers are slow according to namebench (feel free to test this again if you are in doubt), you really want to change these nameservers. You have multiple options to do so:

  • Go to your router’s configuration page (most likely located on, or and use the GUI to change the DNS server(s)
  • Most operating systems (even mobile operating systems like Android and iOS) will allow you to change the DNS servers within the device itself.


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