Exchange 2010 co-existing with Exchange 2003← Back
I’m using the transition method to upgrade from Exchange 2003 to Exchange 2010 for approximately 250 mailboxes with all roles on a single server. Here are a few notable points if you're perfoming the migration.
This guide is accurate and details all the steps necessary to perform the migration from start to finish.
When configuring webmail through Exchange shell, you need to set the LegacyRedirectType manual OWA redirection method instead of having it automatically redirect e.g.
Set-OWAVirtualDirectory <EX2010SVR>\OWA* ` -Exchange2003URL https://<EX2003SVR>/exchange ` -LegacyRedirectType manual
If you try to use the proxy method, you will get HTTP 500 errors when a user on the 2003 server logs in.
If you publish OWA through ISA or TMG, include your Exchange 2003 webmail hostname in your UC SSL certificate so that you can use Single Sign-on on the listener. That way when a user logs into Exchange 2010 OWA but is still on the 2003 mailbox server, they only need to enter their credentials once instead of entering them again when redirected to the Exchange 2003 OWA.
If publishing your Exchange server through ISA or TMG, you need to set your Exchange Web Services virtual directory ExternalURL to match your autodiscover rule eg.
Set-webservicesvirtualdirectory YOURSERVER\* ` -ExternalURL https://autodiscover.yourdomain.com/EWS/Exchange.asmx
Don’t update your Exchange 2003 Recipient Policies until you have moved all users over to Exchange 2010. This will save you having to go through and manually reconfigure the correct email addresses on all your users when your newly converted Email Address Policies don’t work as expected.