# Blocking Cookies

An HTTP cookie is a piece of information that the client and the server exchange to store specific data like authorization details, user preferences, analytics, and others.

As a developer, you might need to test your client or server application as if receiving cookies is explicitly blocked.

With Fiddler Everywhere, you can create a rule that automatically blocks the sending and receiving of cookies.

## Creating a "Block Cookies" Rule

Create a "Block Cookies" rule by setting the following actions through the [Rules Builder](https://www.telerik.com/fiddler/fiddler-everywhere/documentation/modify-and-filter-traffic/modify-traffic-with-rules).

1. Create an **Update Request Header** action and remove all pre-set values for the `Cookie` header.
2. Create an **Update Response Header** action and remove all pre-set values for the `Set-Cookie` header.

This sample Fiddler rule matches all sessions and explicitly blocks all cookies.

![Creating "Block Cookies" rule](https://www.telerik.com/fiddler/fiddler-everywhere/documentation/assets/ecb47b60a8c776003efdc9d9184d39f1/adv-tech-block-cookies.png)

Once the rule is created, enable the **Rules** tab, toggle the rule switch, and start capturing traffic.

![Activating the "Block Cookies" rule](https://www.telerik.com/fiddler/fiddler-everywhere/documentation/assets/8f1bafb08a2caae550d76b659ecc304e/adv-tech-block-cookies-active-rule.png)

Download a ready-to-use <a href="https://github.com/telerik/fiddler-everywhere/tree/master/rules/block-cookies" target="_blank">"Block Cookies"</a> rule as a FARX file, which you can import through the Rules toolbar.

## See Also

* [Learn more about the Rules functionality in Fiddler Everywhere here...](https://www.telerik.com/fiddler/fiddler-everywhere/documentation/modify-and-filter-traffic/modify-traffic-with-rules)
* [Learn more about all rules presets in Fiddler Everywhere here...](https://www.telerik.com/fiddler/fiddler-everywhere/documentation/rules-presets)
* [Learn more on how to organize your rules here...](https://www.telerik.com/fiddler/fiddler-everywhere/documentation/modify-and-filter-traffic/organizing-rules)
* [Learn more about the matching conditions here...](https://www.telerik.com/fiddler/fiddler-everywhere/documentation/modify-and-filter-traffic/conditions-and-actions#conditions)
* [Learn more about the supported actions here...](https://www.telerik.com/fiddler/fiddler-everywhere/documentation/modify-and-filter-traffic/conditions-and-actions#actions)
* [Learn more about final and non-final rules here...](https://www.telerik.com/fiddler/fiddler-everywhere/documentation/modify-and-filter-traffic/conditions-and-actions#final-and-non-final-actions)
* [Learn more about using breakpoints here...](https://www.telerik.com/fiddler/fiddler-everywhere/documentation/modify-and-filter-traffic/breakpoints)