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 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 for the same purpose. For this example, the expression would be the following:

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