We currently have a single Exch 2003 server with a Sonicwall Emailsecurity spam filter acting as a smart host.
I will be adding an Exchange 2010 server to our network soon and gradually moving our mailboxes over to it, then decommissioning the old server.
Users connect to our server from the internet via IMAP, POP3, SMTP (port 587), and OWA, and activesync (iPhones).
Will it be possible to retain the Sonicwall as a smart host while the 2 exchange servers are in use?
We are not currently using SSL, but it seems it is required with the new server. What issues will that raise?
If I have major problems can I easily fall back to just the old server?
Thank you.