I have exhange 2007 with exchange 2003. I currently can do the following:
send Email between 07 and 03.
send Email externally from 03.
Recieve email to 03 and 07 and between 07 to 03.
cannot send email to external from 07.
I created the send connector for the internet with the following:
smpt * 1
DNS mx record checked
Source server is 07 server
There is also a second send connector with the following:
smtp * 1
dns mx record checked
source server is exchange 03 server.
I originally had this problem and went into exchange 03 and under the smpt virtual server under authentication i checked integrated windows authentication and alll of a sudden all of the 07 emails that were queued went out. After that original send i have not been able to send anymore. I have changed nothing since then except for removing the domain name in front of user name during the owa log in.
btw i am running this on a 2008 r2 server in an server 2003 domain.