Steve asked me a question the other day about Exchange 2007 server roles and where he could install POP and IMAP services. He’d previously installed these services on a cluster and wondered where he could install them. So I checked around for something on the web, with all of the Beta 2 documentation, things are changing and being updated regularly. I found this on one of our internal mailing lists however (thanks Mike)
In E2K3, there was no real distinction between server roles. All protocol heads were available on all roles.
In E2K7, there is a clear distinction of what services are available on which roles:
– SMTP runs on HUB/Edge
– POP/IMAP/OWA/Airsync/OutlookAnywhere (aka RPC/HTTP) runs on CAS (if you wanted the CAS to be able to accept mail for POP/IMAP clients, then you’d also need to install the Hub transport on that server)
– The mailbox is just about storage and the core MAPI protocol
If you want a single server to have both SMTP & POP/IMAP on them, then you will need to install the HUB & CAS roles (You cannot install the Edge role on a server which has the CAS role on it).