How to Block Microsoft Exchange Autodiscover requests

Incorrect configured Microsoft Exchange Autodiscover service can trigger your web logs with 404s from GET and POST requests for variations of autodiscover.xml.

To resolve this issue you can use the following in Cloudflare. This example uses a regular expression to block autodiscover.xml and autodiscover.src requests(Action should be Block):

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

Resources:

• Block Microsoft Exchange Autodiscover requests
• Controlling Outlook Autodiscover behavior
• Outlook Autodiscover decision process | Choosing the right Autodiscover method
• Summary of Outlook Autodiscover Order