Major Help Needed - IIS SMTP

[AdminStooge]

We are implementing new IIS SMTP servers in our DMZ and when testing internal to external email we get the following error:
You do not have permission to send to this recipient. For assistance, contact your system administrator.
<clustered exchange environment #5.7.1 smtp;550 5.7.1 Unable to relay for *@gmail.com>

We are able to receive external email but can not reply.

PLEASE HELP

 

[ShackDaddy]

Under the SMTP Virtual Server properties, did you configure the Relay portion of the Access tab to allow your internal mail server to forward through the IIS SMTP server? By default, forwarding is disabled for everything. You will have to add the source IPs of your mail servers to be able to get things out.

ShackDaddy