Answer: In Exchange server 2007 and 2010 configuring mail relay is not a simple process as with Exchange server 2003.
In order to configure mail relay in Exchange Server 2010 we need to create a new Receive Connector and specify the IP address of the server that will be allowed to relay messages.
To configure mail relay on exchange server 2010 follow the steps below:
Open EMC -> Server Configuration -> Hub Transport
In the Right Menu click on New Receive Connector
Type a Name and select Internal Receive connector
In the Remote Network Settings remove the IP address and click on add to add the IP address of the server that will relay messages.
Type the IP address of the server.
Click On New and Finish.
To Allow Anonymous Users \ Server to send email using your Exchange Server we need to set permission on the connector.
Double Click on the Connector and Go to the Permission Group Tab and Tick the Anonymous Users check box Click Apply and Save.
You can also use the other tabs to modify the connector.