Question : Exchange 2010 coexistence with Exchange 2003

Hi there,

I currently have an exchange 2010 and exchange 2003 server in coexistence. I have pointed all the ports on my router from the old server to the new server. When I try to access a mailbox on the 2010 server through OWA I have no issues. However when I try to access one on the 2003 server I get the following error:

Your request couldn't be completed because no server with the correct security settings was found to handle the request. If the problem continues, contact your helpdesk.

Any help would be greatly appreciated. Thanks

Answer : Exchange 2010 coexistence with Exchange 2003

If you install another CAS temporarily and then forward your OWA/ActiveSync rules to this then it will be able to proxy for both the 2003 server and the 2010 server.

Just don't install the mailbox role.