I ran into an issue where email delivery between different AD sites were not working as expected. To be more clear, emails sent by hub transport server in one AD site to another transport server in another site was having issues. SMTP communication between transport servers in 2010 uses an “invisible” send connector which is configured on all transport servers at the time of installation.
This send connector is called “Intra Organization Send Connector” and is not visible in EMC or Shell. But, to troubleshoot any issue, you can enable protocol logging on this connector just as you would on a normal send or receive connector.
Logging is disabled by default on this connector. Running Get-TransportServer “servername” | fl *intra* shows the same.
Run the following command in the Exchange Shell to enable logging on the intra org send connector.
Set-TransportServer “servername” –IntraOrgConnectorProtocolLoggingLevel Verbose
The logs are written to the Send Connector protocol log (C:\Program Files\Microsoft\Exchange Server\V14\TransportRoles\Logs\ProtocolLog\SmtpSend by default).
As soon as you finish troubleshooting, disable the logging by running Set-TransportServer “servername” –IntraOrgConnectorProtocolLoggingLevel None.