Question : ActiveSync Issues in Exchange Co-Existance Environment

This is a bit long winded so please bear with me! Our problem is to do with ActiveSync proxying by the CAS role of Exchange 2007.

Our client has a network consisting of 3 internal domains. The main domain at the moment user Exchange 2003, another domain is also Exchange 2003, with the final domain running with Exchange 2007. I am currently implementing a new Exchange 2007 environment for the primary domain and have come across an issue with ActiveSync. The new environment consists of 2 Exchange 2007 servers (one running Mailbox role, one running Hub Transport and Client Access roles) running in tandem with the existing single Exchange 2003 server. I have installed a valid SSL certificate on the Exchange CAS server already. When a user's account is on the Exchange 2007 server, the ActiveSync and OWA work flawlessly. When the user's account is still on the Exchange 2003 server the OWA works flawlessly in that the CAS server takes the login request on the /exchange directory and shows the user the 2003 OWA experience as it should. However, the ActiveSync is not proxying as predicted. As it the usual case, the Windows Mobile device error code is useless (0x85010004). There are no entries in Event Viewer; in fact the only entry in any log I can find is in the IIS log as follows:

2009-01-19 19:14:49 10.0.0.62 POST /Microsoft-Server-ActiveSync/default.eas User=test&DeviceId=BAD**************************182&DeviceType=PocketPC&Cmd=GetHierarchy&Log=Error:NoMailboxServer_ 443 ********.co.uk\test 86.**.**.** MSFT-PPC/5.2.1400 403 0 64 62

The key to this being the Error:NoMailboxServer_ 443 I suspect. Now... I can't find ANY information on this error message. Basically does anyone have any ideas? I have tried all sorts of fixes and cannot get it to work.

Answer : ActiveSync Issues in Exchange Co-Existance Environment

If you have pinned it down to being the backend server, which is what I think it is, my standard procedure at the moment is to reset the virtual directories on all backend Exchange 2003 servers where a CAS will be placed in front.
http://support.microsoft.com/default.aspx?kbid=883380

Once the reset is complete, the backend servers are not touched and all traffic for OWA etc is pushed through the CAS.

-M