I have an SBS 2003 Standard edition server. We have a scenario where office users will be using exchange to send and recieve email (via outlook 2003). By default, the SBS SMTP connector is the only connecter used at present to send mail. Also, we have 10 shops that pop3 into the server for mail. What i want to do is for the shops give them the address of the server to use as their smtp server, but lock it down so they can only send to the business domain ie. mydomain.com. I still want all office users to be able to send to who ever they want to. How do i do this the most effective way?