MSExchange Autodiscover 2

  • Article

 

This article provides an explanation and possible resolutions for a specific Exchange event. If you don't find what you’re looking for here, try searching Exchange 2010 Help.

Details

Product Name

Exchange

Product Version

14.0

Event ID

2

Category

Web

Symbolic Name

ErrWebAnonymousRequest

Message Text

Anonymous Request received from HostAddress:"%1", HostName:"%2". Invalid Autodiscover site configuration. To fix the problem remove Anonymous access.

Explanation

This Error event indicates that the Microsoft Exchange Autodiscover service was unable to process anonymous requests from an Autodiscover client, for example, an Outlook client. An invalid Autodiscover site configuration and an anonymous client request could cause this error. 'HostName' in the error message text refers to the Domain Name System (DNS) name of the remote client.

Autodiscover requires authenticated clients to connect by using either of these methods:

  • The client may use a Secure Sockets Layer (SSL) connection to perform Active Directory lookups to find the requested mailbox database.

  • The client may provide URLs of Exchange services such as the Availability service.

We do not recommend that you enable anonymous authentication as this will give spammers access to e-mail addresses. A HTTP 403 error is sent to the client.

User Action

To resolve this error, do the following:

  • Check the Autodiscover virtual directory site configuration settings on the Exchange Client Access server (CAS) and make sure SSL is selected for Basic or Integrated Windows authentication (also known as NTLM or Kerberos authentication).

  • Follow these steps to disable Anonymous access in the Autodiscover virtual directory on the Client Access server.

    1. In Internet Information Services (IIS) Manager, locate the Autodiscover virtual directory.

    2. Right-click Autodiscover virtual directory and select Properties.

    3. On the Directory Security tab, under Authentication and access control, click Edit.

    4. In the Authentication Methods screen, clear Enable anonymous access.

For more information about the Autodiscover service, see Managing the Autodiscover Service.

For More Information

If you are not already doing so, consider running the Exchange tools, which have been created to help you analyze and troubleshoot your Exchange environment. These tools can help make sure that your configuration aligns with Microsoft best practices. They can also help you identify and resolve performance issues and improve mail flow. To run these tools, go to the Toolbox node of the Exchange Management Console. To learn more about these tools, see Managing Tools in the Toolbox.