After so many years of being available, the Scoped property of Send Connectors is still confuses some Exchange administrators, or simply goes by unnoticed.
So what exactly is a Scoped Send Connector? Simply put, when we configure a send connector as scoped, we are stating that only Exchange 2007/2010 Hub Transport or Exchange 2013/2016 Mailbox servers in the same Active Directory (AD) site as the send connector can use it. If this option is not selected, then the connector can be used by any Exchange server in any AD site in the same Exchange organization.
But what is the point of this option if we need to specify the Source Servers for the send connector? Doesn’t this option stipulate which Exchange servers can use the connector?! Well, not exactly...
The source servers for a send connector determine the destination Exchange server for mail that needs to be routed through the send connector. The send connector scope controls the visibility of the connector within the Exchange organization.
Once again, send connectors are by default visible to all the Exchange servers in the entire AD forest, and are used in routing decisions. However, we can limit a send connector’s scope so that it is only visible to other Exchange servers in the same AD site. The send connector is invisible to Exchange servers in other AD sites, and is not used in their routing decisions. A send connector that is restricted in this way is said to be scoped.
To configure scoped send connectors in the EAC (assuming Exchange 2013/2016), we select Scoped send connector in the Address space section of the new send connector wizard, or on the Scoping tab in the properties of existing send connectors (as previously shown).
When using the Exchange Management Shell, we use the IsScopedConnector parameter on the New-SendConnector and Set-SendConnector cmdlets.