Dear All, I have a question about Exchange 2007 SP1 architecture in a mixed environment with Exchange 2003 SP2, regarding EAS access. We have the following situation: Exchange 2007 SP1 mailbox servers and CAS servers in one central datacenter (high bandwidth/low latency) Exchange 2003 SP2 mailbox servers spread over multiple remote sites all over the world Windows Mobile (5/6) ActiveSync users that are connecting to our Exchange environment via the central data center where the Exchange 2007 SP1 servers are also located Since the connection to the remote sites are low bandwidth/high latency connections, ActiveSync (EAS) connectivity is normally solved using CAS-to-CAS proxying. But we are now in a transition phase that will take at least one year where Exchange 2003 mailbox servers still exist on remote sites. My question: Is it possible to place a CAS server in each remote site (where a 2003 mailbox server is located) and configure CAS-to-CAS proying? If not, what is the alternative? Regards,Helmuth Snoeijen