Some of our Outlook clients are still connecting to the old Exchange 2010 Server. Some problems with the physical server led us to move mailboxes over about 2 weeks ago. We want to decommission the old server but whenever we do a test shut down of services on the old server we're still seeing some Outlook 2010 clients getting auth prompts.
This problem seems to be intermittent. After hours a week ago I had shut down Exchange services on the old server after hours and was still able to open Outlook and use OWA from inside and also use Outlook Anywhere, OWA and ActiveSync from outside.
So far Netstat is giving us a lot of info but isn't giving us the final answer. We used our Remote Desktop server for troubleshooting since we do have a fair number of staff connected to that from remote locations. On this server Outlook is open for a lot of these sessions. Using Netstat I see that there are SOME connections to the old server at 10.134.144.239:
C:\Users\citiadmin>netstat -an | findstr 239
TCP 10.134.144.240:60544 10.134.144.239:25237 ESTABLISHED
TCP 10.134.144.240:62042 10.134.144.239:25237 ESTABLISHED
This compares to connections on our new server at 10.134.144.220:
C:\Users\citiadmin>netstat -an | findstr 220
TCP 0.0.0.0:49220 0.0.0.0:0 LISTENING
TCP 10.134.144.240:52185 10.134.144.220:10224 ESTABLISHED
TCP 10.134.144.240:60539 10.134.144.220:10224 ESTABLISHED
TCP 10.134.144.240:60541 10.134.144.220:10296 ESTABLISHED
TCP 10.134.144.240:62041 10.134.144.220:10224 ESTABLISHED
TCP 10.134.144.240:62045 10.134.144.220:10296 ESTABLISHED
TCP 10.134.144.240:63118 10.134.144.220:10296 ESTABLISHED
TCP 10.134.144.240:63220 10.134.144.220:10224 ESTABLISHED
TCP 10.134.144.240:63221 10.134.144.220:10296 ESTABLISHED
TCP 10.134.144.240:64697 10.134.144.220:10224 ESTABLISHED
TCP 10.134.144.240:64701 10.134.144.220:10296 ESTABLISHED
TCP [::]:49220 [::]:0 LISTENING
Sometimes there is a connection to port 135 on the old server, too. If I look at Netstat -b on the old mail server it looks like the connection endpoints are connections to the Microsoft.Exchange.RpcClientAccess.Service.exe service. If I bounce that service the connections to the old server drop but get established almost immediately (as I expect Outlook should/would do).
There are more connections to the new server but still there are some connections on the old server. It's actually not that easy to replicate this issue because it does seem to be sporadic. When I shut down the old server yesterday I heard a shout from a few people around our department. I started services back up, asked those people to dismiss the auth prompt. When they dismissed this prompt Outlook went back to behaving normally.
Some other possibly relevant info:
* We have set up a CNAME for autodiscover for autodiscover.[ourdomain].[tld].
* I have checked that the internal URL for services under Server Configuration -> Client Access are all pointed to the new server (on both the new and old Exchange 2010 servers).
* Both new and old Exchange Servers are at the same version and patch level.
* The Pub Folder assigned to the mailbox database is on the new server.
* This issue seems to be affecting existing connections/profiles and we haven't heard about any issues with creating new profiles using Outlook 2010's default methods.
What can we do to track down why Outlook clients are still looking at the old server? Can we safely just decommission and expect that whatever settings are pointing over there will be removed cleanly?