In our Exchange environment we have a mailbox server, Hub/CAS server and an Edge server. We recently moved our mailbox and Hub/CAS servers to the same AD site (subnet) as our Edge server is located. After the move, our recieve connector for relaying our internal devices has stopped working for only the subnet it is now located in 10.15.100.x. I added all of the IP addresses that need to send email with no luck. Any device that is located outside of the 10.15.100.x site still work. Email between the Edge and Hub is flowing without any problems. The relay is setup as option 1 on http://msexchangeteam.com/archive/2006/12/28/432013.aspx
. If I setup the client to authenticate, I am able to send email, but not all of my devices support this option. Thanks.