Exchange RPC over HTTP Stopped Working

Posted on 2006-05-27
Last Modified: 2012-06-21
I have a single Exchange 2003 SP2 server with one Outlook client connecting via RPC over HTTP.  After working for several weeks without a hitch it stopped working - The Outlook client cannot connect.  Nothing has changed on my firewall and I did not modify anything in the Exchange server during the period in which it failed.  There are no obvious errors in the system logs.

In the document I used to set up RPC over HTTP with a single Exchange server (no back-end/front-end stuff), it tells you to test it by going to http://your.server's.FQDN/rpc, authenticating with "domain\username."  You are supposed to get an error that says "This page cannot be displayed.  HTTP Error 403.2 - Forbidden: Read access is denied" as a confirmation that RPC is working, but instead it keeps asking me for my username and password.  I went back through the entire document to verify that all the setting are still as they had been configured and they are.

Any guidance on how to troubleshoot this would be appreciated.
Question by:ryoxthimer
    1 Comment
    LVL 4

    Accepted Solution

    This link will help you troubleshoot the issue:

    For troubleshooting problems associated with connectivity it is often advisable to disable the protocol failback.  When Outlook 2003 cannot make an RPC over HTTP connection it will atuomatically use the TCP/IP protocol to make an RPC over MAPI connection.  To do this modify the following key in the registry


    Create an entry DisableRpcTcpFallback and set it to the DWORD value of 1.  To reauthorize fallback you can set this value to 0.

    You may also wish to enable Outlook 2003's RPC tracing.  You configure this under Tools | Options | Other | Advanced Options.  Ensure the Mail Logging (troubleshooting) checkbox is enabled.  With this enabled (after restarting Outlook) Outlook will write events to the machines Application log.

    If this tracking is insufficient you can alternately enhance this through creating some additional registry entries and replacing certail .dll files on the client.  Under the HKEY_CURRENT_USER\Software\Microsoft\Office\11\Outlook\RPC subkey create the following entries:  RpcTraceEnable, RpcStackTrace,RpcDumpToFile, and RpcOutputDir.  Additionally you will need to obtain new versions of the following dlls from Microsoft.  emsmdb32.dll, emsabp32.dll, emsui32.dll, and smsapi32.dll.

    Finally you are likely to achieve much better performance when you change the RPC binding order to look first to the TCP/IP stack.  To do this modify the following registry key:


    Change the Rpc_Binding_Order to ensure that ncacn_ip_tcp is listed before the other entries, including ncalrpc

    Featured Post

    Don't lose your head updating email signatures!

    Do your end users still have the wrong email signature? Do email signature updates bore you or fill you with a sense of dread? You can make this a whole lot easier on yourself by trusting an Exclaimer email signature management solution. Over 50 million users should you!

    Join & Write a Comment

    Email statistics and Mailbox database quotas You might have an interest in attaining information such as mailbox details, mailbox statistics and mailbox database details from Exchange server. At that point, knowing how to retrieve this information …
    Set OWA language and time zone in Exchange for individuals, all users or per database.
    In this video we show how to create an email address policy in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.:  First we need to log into the Exchange Admin Center. Navigate to the Mail Flow…
    To add imagery to an HTML email signature, you have two options available to you. You can either add a logo/image by embedding it directly into the signature or hosting it externally and linking to it. The vast majority of email clients display l…

    730 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    16 Experts available now in Live!

    Get 1:1 Help Now