This is the 5th chapter from the guide How to setup and configure Exchange server 2010 behind Microsoft Forefront Threat Management Gateway. This is a continuation from the 4th chapter which covers Creating a send connector so that you can send emails to people outside your organization.
To enable receiving email from outside your organization, navigate to Server Configuration – Hub Transport. Double click on Default receive connectors and ensure that the checkbox is ticked for Anonymous users on the permissions group tab (as seen in Figure 1).
Exit out of the Default Receive Connectors dialog box. Double click on the Client receive connectors and navigate to the General tab. In the textbox for ‘Specify the FQDN this connector will provide in response to HELO or EHLO’ enter your top level domain name instead of .local extension (as shown in Figure 2). If this information is not changed, then you are unable to connect through the secure port to your SMTP server.
The following chapter (6th chapter) will explain Configuring Accepted Domains on Exchange to host email for different domains.