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How to Override your DNS with GTmetrix

Get GTmetrix to use a custom DNS when performing tests.

There are a number reasons why you may need GTmetrix to use a custom DNS:

  • Redirecting development/staging sites to the production site’s real hostname
  • Accessing geoblocked resources
  • Blackholing resources to test for effects on overall performance

With our Override DNS feature, you can now specify a hostname and IP address to ensure that your site is analyzed the way you need it to be.

Override DNS is available for PRO users only. Upgrade to a PRO plan today!


What does Override DNS do?

In simple terms, a DNS acts like a phone directory between domain names and IP addresses.

For example, typing in your address bar would send that domain to a DNS server, which would then route it to something computers understand better, like an IP address (in this case,

A local DNS looks up hostnames and matches them to their corresponding IP address for computers to understand better.


Most DNS servers are operated by Internet Service Providers (ISPs) who keep them updated constantly. However, there are occasions where you may want the domain name to be routed differently – this is where a custom DNS would be useful.

Overriding your DNS would essentially tell domain names to go to IP addresses you designate, and not what the general DNS servers would typically define.

Overriding a DNS lets you tell GTmetrix where to go instead of the proper destination.


GTmetrix simply provides the ability to override hosts and IP addresses to direct them to your desired server.



How to use it

To override your DNS, follow the steps below:

1) Enter your URL into the Analyze field, and click on Analysis Options

Click on Analysis Options to expand the menu.


2) Expand the Advanced Options field

Expand the Advanced Options field to reveal the Override DNS feature.


3) Click “Add a Custom DNS” under the Override DNS section

A Host field and IP Address field will appear.

Add as many custom DNS’s as needed.


4) Input the host and IP address corresponding to your custom DNS

For example:

Host Name:

When you analyze your page, GTmetrix will use the custom DNS settings you’ve inputted.

Note: Sites using https:// and SSL will still require the newly pointed server to have their SSL certificate properly set up, or GTmetrix will be unable to analyze.


Save it as a Preset!

For convenient access, be sure to save your custom DNS as a preset.

Create a custom DNS preset for quick analysis .


Learn more about how to use GTmetrix analysis presets.


Override DNS is available to PRO users only

GTmetrix Developer Toolkit

Override DNS is available on all PRO plans, along with more Advanced Analysis Options like Simulated Devices, Analysis Presets, Custom Connection Speeds and more.

As a PRO user, you’ll also get an enhanced GTmetrix experience with: Priority access for tests, More Monitored Slots, Hourly Monitoring (select plans only), Remote Location Monitoring (including Premium Test Locations), and more.

Go PRO and Override your DNS today

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