We have recently added our first Exchange 2007 Server to our Windows Server 2003 / Exchange 2003 environment. We tested this server (EXCH07A) and found that everything works fine. Sending and receiving from/to users on the Exchange 2003 Server occurs without any issues. We acquired a beefier server and installed a second instance of Exchange 2007 on this new box. While testing with the new server (EXCH07B), we find that it receives mail from the Exchange 2003 environment but cannot send to it. It CAN send mail to EXCH07A. Does a 2nd routing group connector need to be created for EXCH07B to the 2003 environment? Or should it be sending through EXCH07A to the 2003 server? Should one have been automatically created during the installation of EXCH07B?