I'd like to understand a few more things about mail flow and coexistence in our 2010/2013 environment.

Emails from users on Exchange 2010 are being routed through the 2013 mailbox servers now to get to the internet, via our edge transport server. Why are they going through 2013, and not going out straight from 2010?

Also, any users with mailboxes on 2013 cannot send emails out to the internet. When I telnet to the edge transport server to send an email, I get the error 550 5.7.1 Unable to Relay. When I checked the logs on the edge transport server that I telnetted to, I saw this:

Received certificate 2015-01-26T11:47:08.401Z,edge01\Internal_Mail_Servers,08D2050B356B6D47,27,192.168.2.2:25,192.168.1.2:22221,,,<THUMPRINT>,Certificate thumbprint 2015-01-26T11:47:08.401Z,edge01\Internal_Mail_Servers,08D2050B356B6D47,28,192.168.2.2:25,192.168.1.2:22221,,,DirectTrust certificate failed to authenticate for CN=EXMB2013_01

• Edited by snorri788 Tuesday, January 27, 2015 1:54 PM formatting

Hi,

this is because Exchange 3013 servers have not been added to the send Connector.Sending internal mail Works since it uses DAG to route the e-mail.

Hi,

this is because Exchange 3013 servers have not been added to the send Connector.Sending internal mail Works since it uses DAG to route the e-mail.

Hi snorri788 ,

Thank you for your question.

Why are they going through 2013, and not going out straight from 2010?

A: SMTP external (from and to Internet) transport in Exchange Server 2013 is handled by CAS server, while on Exchange 2010 SMTP transport is handled by Hub or Edge transport server. Most of functionality from Hub transport server 2010 is now located on MBX server in Exchange 2013. SMTP traffic in coexistence scenarios is enabled by default, and we should have mail flow between 2010 and 2013 and vice versa working. However, OWA, Active Sync and Outlook Anywhere should be directed to CAS 2013 once we introduce it to we current Exchange organization.

So message flow go to Internet by Exchange 2013. Send connector should be created on Exchange 2013 by the following link:

https://technet.microsoft.com/en-us/library/jj657457(v=exchg.150).aspx

Then, by error information, the Edge subscription didnt sync, we could refer to the following link to rebuild Edge subscription:

https://technet.microsoft.com/en-us/library/bb123800(v=exchg.150).aspx

If there are any questions regarding this issue, please be free to let me know. 

Best Regard,

Jim

• Marked as answer by Simon_WuMicrosoft contingent staff, Moderator 21 hours 41 minutes ago

Hi snorri788 ,

Thank you for your question.

Why are they going through 2013, and not going out straight from 2010?

A: SMTP external (from and to Internet) transport in Exchange Server 2013 is handled by CAS server, while on Exchange 2010 SMTP transport is handled by Hub or Edge transport server. Most of functionality from Hub transport server 2010 is now located on MBX server in Exchange 2013. SMTP traffic in coexistence scenarios is enabled by default, and we should have mail flow between 2010 and 2013 and vice versa working. However, OWA, Active Sync and Outlook Anywhere should be directed to CAS 2013 once we introduce it to we current Exchange organization.

So message flow go to Internet by Exchange 2013. Send connector should be created on Exchange 2013 by the following link:

https://technet.microsoft.com/en-us/library/jj657457(v=exchg.150).aspx

Then, by error information, the Edge subscription didnt sync, we could refer to the following link to rebuild Edge subscription:

https://technet.microsoft.com/en-us/library/bb123800(v=exchg.150).aspx

If there are any questions regarding this issue, please be free to let me know. 

Best Regard,

Jim

• Marked as answer by Simon_WuMicrosoft contingent staff, Moderator Friday, February 06, 2015 2:08 PM

Thanks Simon for that. 

I found out that the solution was the Exchange certificate on the Mailbox servers was not assigned to SMTP services. Once that was set then mail flowed OK.

• Marked as answer by snorri788 20 hours 45 minutes ago

Thanks Simon for that. 

I found out that the solution was the Exchange certificate on the Mailbox servers was not assigned to SMTP services. Once that was set then mail flowed OK.

• Marked as answer by snorri788 Friday, February 06, 2015 3:04 PM