Something happened the other day that we do not understand. I've read a ton of stuff about RPC over HTTPS and how Outlook connects to Exchange but I wasn't ready for this one. In preparation for a large group of our users being migrated to a network outside of our firewall we had enabled RPC over HTTPS in our environment and configured the workstations for these users that are going to be migrated to use RPC over HTTPS as the only Outlook 2007 profile. We have one Exchange 2003 Front End server which is also our RPC over HTTPS front end server. We have two back end Exchange 2003 Mail servers. The group of users is still inside our internal network and we just wanted to test the RPC over HTTPS to guage whether we would need another front end server. At this point all is fine and dandy. Everything worked just perfect. I could see the users actually connecting over port 443 to the front end server which then brokered their connection to the back end servers. But the other day our front end RPC over HTTPS server went down and we were concerned that all those users that had been converted over to RPC over HTTPS would not be able to access email unless they added another profile or removed the rpc over https. Low and behold those users who had been configured for rpc over https were still able to open Outlook 2007 and login to Exchange. My question is how were these guys able to login to Exchange from Outlook 2007 when the profile was configured for RPC over HTTPS and not other profies were configured? Will Outlook automatically start looking for Exchange servers in Active Directory if it can't find it's proxy server? Thanks so much in advance for an explanation to this question. Best Regards, Fred Towery

On one of the Outlook clients, hold the Ctrl key down, click the Outlook icon in the system tray, and select Connection status. You'll see the protocol being used (HTTP or TCP/IP) to connect to the server. -- Ed Crowley MVP "There are seldom good technological solutions to behavioral problems." . "fredtowery" wrote in message news:85441c9b-1af1-4614-a5f8-8864692f09a9... Something happened the other day that we do not understand. I've read a ton of stuff about RPC over HTTPS and how Outlook connects to Exchange but I wasn't ready for this one. In preparation for a large group of our users being migrated to a network outside of our firewall we had enabled RPC over HTTPS in our environment and configured the workstations for these users that are going to be migrated to use RPC over HTTPS as the only Outlook 2007 profile. We have one Exchange 2003 Front End server which is also our RPC over HTTPS front end server. We have two back end Exchange 2003 Mail servers. The group of users is still inside our internal network and we just wanted to test the RPC over HTTPS to guage whether we would need another front end server. At this point all is fine and dandy. Everything worked just perfect. I could see the users actually connecting over port 443 to the front end server which then brokered their connection to the back end servers. But the other day our front end RPC over HTTPS server went down and we were concerned that all those users that had been converted over to RPC over HTTPS would not be able to access email unless they added another profile or removed the rpc over https. Low and behold those users who had been configured for rpc over https were still able to open Outlook 2007 and login to Exchange. My question is how were these guys able to login to Exchange from Outlook 2007 when the profile was configured for RPC over HTTPS and not other profies were configured? Will Outlook automatically start looking for Exchange servers in Active Directory if it can't find it's proxy server? Thanks so much in advance for an explanation to this question. Best Regards, Fred Towery Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Thanks Ed, but I can't really do it now since my front end server is back online. I did however look at my own connection right now which shows my back end server as the server and my protocol as https. I thought that I was making the connection through the front end proxy server which then brokered the connection to the back end server. I don't understand how the front end server can be down and the clients still connect via rpc over https to Exchange without a front end server. If the back end servers are available will it automatically connect to them using any protocol that works? Thanks again, Fred Towery

I'd take it offline during off-hours for a few minutes and watch what happens. There are a lot of settings in Outlook for this kind of behavior, and I'm not convinced that any of them have the expected effects! -- Ed Crowley MVP "There are seldom good technological solutions to behavioral problems." . "fredtowery" wrote in message news:4c689fb1-6666-41ae-ae19-17480315da5e... Thanks Ed, but I can't really do it now since my front end server is back online. I did however look at my own connection right now which shows my back end server as the server and my protocol as https. I thought that I was making the connection through the front end proxy server which then brokered the connection to the back end server. I don't understand how the front end server can be down and the clients still connect via rpc over https to Exchange without a front end server. If the back end servers are available will it automatically connect to them using any protocol that works? Thanks again, Fred Towery Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Hi Fred, When Exchange Front End server stop working, Outlook first try to connect to Exchange by RPC over Https Protocol and it failed, then it will use TCP/IP protocol instead of RPC over Https. By using TCP/IP protocol, outlook connect to GC/DC and mailbox store directly. Since the users are in your internal domain, they are able to do this. If it’s possible, you can shut down the front-end server for testing. Then open Outlook and check the Connection status.

Thanks Gen Lin, I will do that next time we have maintenance. Best regards, Fred Towery