---
title: Block Microsoft Exchange Autodiscover requests
description: Block Microsoft Exchange Autodiscover requests.
image: https://developers.cloudflare.com/core-services-preview.png
---

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# Block Microsoft Exchange Autodiscover requests

In some cases, Microsoft Exchange Autodiscover service requests can be "noisy", triggering large numbers of `HTTP 404` (`Not found`) errors.

This example [custom rule](https://developers.cloudflare.com/waf/custom-rules/create-dashboard/) blocks requests for `autodiscover.xml` and `autodiscover.src`:

* **When incoming requests match**:  
Use the expression editor:  
`(ends_with(http.request.uri.path, "/autodiscover.xml") or ends_with(http.request.uri.path, "/autodiscover.src"))`
* **Then take action**: _Block_

Alternatively, customers on a Business or Enterprise plan can use the `matches` [comparison operator](https://developers.cloudflare.com/ruleset-engine/rules-language/operators/#comparison-operators) for the same purpose. For this example, the expression would be the following:

```

(http.request.uri.path matches "/autodiscover.(xml|src)$")


```

```json
{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/waf/","name":"WAF"}},{"@type":"ListItem","position":3,"item":{"@id":"/waf/custom-rules/","name":"Custom rules"}},{"@type":"ListItem","position":4,"item":{"@id":"/waf/custom-rules/use-cases/","name":"Common use cases"}},{"@type":"ListItem","position":5,"item":{"@id":"/waf/custom-rules/use-cases/block-ms-exchange-autodiscover/","name":"Block Microsoft Exchange Autodiscover requests"}}]}
```