There are many factors one needs to take into account when planning a migration from a locally managed Microsoft Exchange server to an externally hosted solution. Of utmost importance is obviously ensuring that no e-mail is lost during the transition and that service disruptions for end users are kept to a minimum. There are a number of crucial points you should remember during the migration.
Firstly, do NOT make any DNS changes until you are certain the new service is provisioned and ready to go.
Secondly, do not take the local Microsoft Exchange server offline until the process is complete. You never know what e-mail may filter through. DNS changes can take a while to propagate to some areas of the internet.
The process, otherwise, can be relatively painless. You may run into trouble with Outlooks’ autodiscover feature, whereby it may keep trying to talk to the local Exchange server despite changing settings. This can be caused by an object called SCP (service connection point) in Active Directory, or may also be caused by an incorrect autodiscover setting in your DNS settings. The SCP issue can be fixed by either modifying a registry key for Outlook on client machines, or by running a couple of Powershell commands. In a management shell type “Set-ClientAccessServer -Identity “SERVERNAME” -AutoDiscoverServiceInternalUri $NULL”
If you have multiple Exchange servers then you will need to run the above command numerous times, substituting SERVERNAME for the name of each server in succession.
Also remember, modifying the autodiscover CNAME entry is a crucial part of ensuring a smooth changeover for all users. You simply need to add a new CNAME entry for autodiscover.yourdomain.com.au to whatever your new managed exchange provider tells you.
One other thing – if you wish to transfer contacts and calendars across to the new server, this process is relatively straightforward. Before the switch over, you can do manual exports at each client PC. Export the entire mail store to PST, or just the contacts and calendars. All you need to do then is import this PST file back into Outlook once the new Microsoft Exchange account is setup. This will then automatically sync all of this re-imported data to the new externally hosted service. Of course, if you want to transfer very large amounts of data, there are other ways to do this directly from the server itself. But that’s for another article!