Hello,we have two cas on a exchange 2003 organisation.We put on the CAS virtual directory /rpc the anonymous acces but at each reboot or every 15 mins approx , this option is automatically cleared.Our reverse proxy doesnt work without this acces.Please help...

Hi, Please understand that when you configure the RPC proxy server, you must set the RPC virtual directory to use Basic authentication, NTLM authentication, or both Basic authentication and NTLM authentication. Outlook can send either Basic authentication or NTLM authentication for the HTTP session, depending on how you have configured the Outlook profile. The RPC proxy server Internet Server API (ISAPI) does not accept anonymously authenticated connections. Besides, what is your CAS server version. With Exchange 2007 RTM, it was not possible to manually turn off an authentication method using the IISManager MMC snap-in, since every 15 minutes the Exchange Services Host Service would automatically re-enable both Basic and NTLM authentication methods in IIS. Meanwhile, Basic authentication works with reverse proxy firewalls. RPC over HTTP Authentication and Security http://technet.microsoft.com/en-us/library/aa996225.aspx Outlook Anywhere changes in Exchange Server 2007 SP1 http://msexchangeteam.com/archive/2007/11/08/447484.aspx Pay attention to the below article, it may can be used in Exchange 2003 pure environment (without exchange 2007 role). I have set the test environment(Exchange Server 2003 with Exchange Server 2007 with CAS role installed existing in one organization), and added the related AllowAnonymous, but unfortunately, the authentication change to basic authentication mode after I rebooted my CAS server. Configuring Computers for RPC over HTTP http://msdn.microsoft.com/en-us/library/aa373592(VS.85).aspx Description of the RPC over HTTP feature and the AllowAnonymous registry entry in Windows Server 2003 http://support.microsoft.com/kb/833003/en-us Hope it helps. Xiu