OK, here is my path:
Internet -> Hosted Spam filter -> Exchange1 -> Exchange2
Exchange2 is down. I want to give my users on that system a way to read their email while we work to bring their server back up. If there were only one server, mail would be getting queued at the spam server and I could direct users to login there and read new, inbound email.
Can I do something similar with Exchange1? Can I have the Exchange2 users login to the Exchange1 server via OWA? Would they be able to see their incoming email or would it be stuck in a queue for delivery to the proper server?
Also, of course, they would like to be able to send outbound email as well.