Hi.

We are currently migrating from Exchange 2007 to Exchange 2013. We have Exchange servers across 3 AD Site (A, B &C). Right now, all our users are on Exchange 2007 except 2-3 test users. Exchange 2013 was installed in site A without any issue. At that moment, mail flow between users from site A to site B keep using Exchange 2007 hub servers in both directions; Exchange 2013 Transport Servers in site A were not used at all.

When we installed Exchange 2013 in site B, mailbox flow between Exchange 2007 users from site A to Exchange 2007 users in site B start using site B Exchange 2013 Transport servers. Why?

Right now, when site A users are sending email to site B, its using site B Exchange 2013 Transport Servers (Site A 2007 Mailbox Server, Site A 2007 Hub Server, Site B Exchange 2013 Transport Server, Site B 2007 Hub Server, Site b 2007 Mailbox Server). When site B users are sending email to site A, its keep using Exchange 2007 hub. (Site B 2007 Mailbox Server, Site B 2007 Hub, Site A 2007 Hub, Mailbox, Site A 2007 Mailbox Server).

Can someone explain why Exchange 2013 transport services are only used in site B and not A? Any documentation I can read that explain the result?

Thank you.

Are there any users in Site A? What is the cost on the Exchange 2013 Connectors

I have around 6,000 users in each site. I don't understand your question about connectorcost. The Connector used was the Intra-Organization SMTP Send Connector and to my knowledge, there is no way to configured it even in PowerShell.

Hi,

In order to troubleshoot the issue more efficiently, I need to clarify some information.

1. In Exchange 2013, there are only two server roles that can be installed: CAS role and MBX role. What's the meaning of Exchange 2013 Transport server?

2. In each AD site, there must be at least three server roles which are CAS, HUB and MBX roles. Based on the description, there are only two Exchange 2007 server roles: MBX and HUB.

3. "When we installed Exchange 2013 in site B, mailbox flow between Exchange 2007 users from site A to Exchange 2007 users in site B start using site B Exchange 2013 Transport servers. Why?"

After you have installed Exchange 2013 in site B, now, in site A and site B, there is an Exchange 2013 in each site. Is it right?

Do you mean it first goes to Exchange 2013 and then to Exchange 2007 when Exchange 2007 users send emails in site A to Exchange 2007 users in site B? If so, I recommend you run the Get-ReceiveConnector cmdlet in site B and post result here for further research.

How do you know whether Exchange 2013 Transport Servers are used or not? Via message tracking log or smtp log, even another way?

5. "Right now, when site A users are sending email to site B, its using site B Exchange 2013 Transport Servers (Site A 2007 Mailbox Server, Site A 2007 Hub Server, Site B Exchange 2013 Transport Server, Site B 2007 Hub Server, Site b 2007 Mailbox Server). When site B users are sending email to site A, its keep using Exchange 2007 hub. (Site B 2007 Mailbox Server, Site B 2007 Hub, Site A 2007 Hub, Mailbox, Site A 2007 Mailbox Server)."

From this description above, I found the followings, where is Site B Exchange 2013 Transport Server in the second sentence?

When site A users are sending email to site B: (Site A 2007 Mailbox Server, Site A 2007 Hub Server, Site B Exchange 2013 Transport Server, Site B 2007 Hub Server, Site b 2007 Mailbox Server).

When site B users are sending email to site A: (Site B 2007 Mailbox Server, Site B 2007 Hub, Site A 2007 Hub, Mailbox, Site A 2007 Mailbox Server).

Best regards,
B

In our Exchange 2013 environment, our servers are multi-roles (CA and MBX).   

In our Exchange 2007 environment, each site has 1 MBX (Cluster) with 2 Transport/Client Servers.

After you have installed Exchange 2013 in site B, now, in site A and site B, there is an Exchange 2013 in each site. Is it right?"

You are correct.

"Do you mean it first goes to Exchange 2013 and then to Exchange 2007 when Exchange 2007 users send emails in site A to Exchange 2007 users in site B? If so, I recommend you run the Get-ReceiveConnector cmdlet in site B and post result here for further research.

You are correct.  

What received connector informations are you interest in?

How do you know whether Exchange 2013 Transport Servers are used or not? Via message tracking log or smtp log, even another way?

                Tracking Log and its show the Intra-Organization SMTP Send Connector

                If I can summarize,

SiteA to Site B : Exchange 2007 at Site A  -->  Exchange 2013 Site B --> Exchange 2007  in Site B.

Site B to Site A: Exchange 2007 at Site B --> Exchange 2007 in Site A.

Thank you.

Hi,

It seems that the issue is ralated to the connector priority. Please find the send connector, I recommend you change the cost of this send connector to a higher value in order to make the priority lower. Then please try again to check the result. You can post the result of running Get-ReceiveConnector here at your convenience.

To change the send connector cost:

1. Locate the send connector.
2. Right click on the connector and choose Properties.
3. Under the Address Space tab, double click the address sapce you want.
4. Change the value of Cost, click OK.

Best regards,
B

The Intra-Organization SMTP Send Connector is not visible either anywhere, not even using ADSI Edit. Its a build-in and hidden connector.

How has this been fixed ? I have the exact same issue, and the send connector is hidden so solution above can not be applied.

Once a second Exchange 2013 server has been installed in another site, Exchange 2010 sends sometimes to this new Exchange 2013 server (with both roles) and sometimes to the right Exchange 2010 hub server although the mailboxes are still on Exchange 2010 server. And those emails disappeared.

Thanks a lot.