We have a software package that uses email relay to send out receipts. We set up the process once in the software package and then just make sure the select few IP addresses are added to Relay in Exchange. This process has worked well for several years using XP machines. We have just started using some Windows 7 machines and the email relay doesn't work on them. I've added their IP addresses to Relay in Exchange, but they still don't work. In fact one PC kept its static IP and the other one got a new IP address. I removed and added both back in. Is there something that needs to be done on the Win 7 side to make this work??