Backdrop: 1 company that split into two. Was one main domain on exchange 5.5, then went to two domains in one forest on exchange 2003. Looking at the pic below, C1 is in the primary domain, C2 is exchange server in the nested domain. But, obviously 1 administrative group. Everything worked like this for the last 7 years with no problems. Last month, I started the transition of company 1 to 2010. Apologies, I didnt expand that one in the pic. The new box is single box with CAS, HUB, and BOX rolls on it. The transition went fairly smooth overall with the help of a few of you here. So, I finally finished moving mailboxes from C1 to the new C2010 last week. Again everything seems to be working ok. Mail was flowing in all directions. But, before decomisioning C1, for testing purposes, I wanted to make sure everything still worked when I take it out of the mix, so I simply shut it down. When I turn off C1, mail flow does not go between C2 and C2010 in either direction. While C1 is turned on it does flow, but not when I turn it off. In the end, C2 is not going to go to 2010 at this time. They will be moving towards a hosted solution in the not too distant future, but not yet. One item I found today in my searching for clues... when I go to C2010 > Rec Config > Mailboxes I can see all of the boxes from both cos, and it shows the correct domains that they are associated with under the Organizational Unit column. But, when I open up the properties of one of the boxes from the C2 and go to the tab Member Of... it does not show the C2 domain groups that they are a part of, only the C1 global groups that I have them a part of. Any suggestions would be great.

Without doing another screen shot here is basically what the results said: Name.....................................................Source....................................................Target C1 to C2.............................................route group 1...........................................route group 2 C1 to C2..............................................route group 2.........................................route group 1 C2 to C1.............................................route group 2..........................................route group 1 C2010 to C1.........................................route group 2010.....................................route group 1 C1 to C2010.............................................route group 1.........................................route group 2010 So, I guess you are correct. on that. How can I add in the route to the C2 in the 2010? As far as the send connectors, I created the send connector on the C2010. But, have not removed the send connectors from either C1 or C2. I was about to do that when this problem showed up and I didnt want to end up where users on C2 could not send emails. Other than email flow between companies, these should be treated as separate companies. Externally flowing emails from C2 should not go thru C1's servers.

RM, Thank you for your patience with me. Just a couple more confirming questions. Since C2 is a separate company and separate domain that is not planning on moving to Exch2010, I did not run the domain prep on that domain. I only did that with the main C1 domain. I do not want email destined for external internet from C2 to go thru the 2010 box. So, first question is, do I have to do the domain prep on C2 before making any of these changes with RGCs. Reading the instructions found : http://technet.microsoft.com/en-us/library/aa997292.aspx and http://technet.microsoft.com/en-us/library/aa996728.aspx It says I need to suppress the minor link states. My second question is again just trying to confirm that after doing the suppression and adding a new RGC will allow mail flow directly between C2 and 2010, but will still have external bound emails from C2 use its own send connector, it wont send it thru the 2010.

That should work by issuing the correct commands from the 2010 server. For the disable link state, this is one of the prereqs for 2010 deployment as listed in Technet. Though if you have a single RGC then you do not need to do this: http://blogs.technet.com/b/exchange/archive/2006/11/01/3395982.aspx Important change from some of our very early documentation: As long as you only have a single RGC between the Exchange 2007 world and the legacy world, you do NOT need to do anything to disable Linkstate. If you have ever seen this guidance, you may ignore it for now. Basically, except for the one link between the two worlds, Exchange 2007 and legacy servers will operate independently with no chance for loops to exist. The true beauty of this is that many smaller customers with only 1 or 2 routing groups will probably never even have to think about this. As long as you have local send connectors with a lower cost that the other Internet facing one (i.e. more attactive that routing to the other site) then mail flow will go out the local send connector for each of your orgs. This is what you have right now - correct? All we want to do is to allow internal mailflow between C2 and the C1 2010 server. Cheers, Rhoderick