We have a SonicWall ES200 that has been running great using Exchange 2003 and Exchange 2007 together. The ES200 forwarded mail to the Exchange 2003 server which distributed the mail. Over this past weekend we decided to remove the Exchange 2003 server, so we transferred everything over to the 2007 server. We changed the forward address within the ES200 from the 2003 Server to the 2007 Server. However after the change all mail from the outside started bouncing back to the sender saying the receipient could not be found.
We created a new receive connector allowing anonymous relay for the IP address of the ES200, but it did not fix the problem. Currently everything has been moved over to the Exchange 2007 server and we left the 2003 server up and running to make sure we continue to receive mail, but we need to take it down ASAP. Any help would be greatly appreciated.