I am having a mail routing issue sending to our second 2003 exchange server. Here is our setup: Exchange 2003 - 2 Servers (different active directory sites) Exchange 2007 - 4 Servers (Single Site) - 2 CAS/HUB servers & CCR Mailbox Cluster When installing the first CAS/HUB server, I selected our main 2003 EX server as the bridgehead server (Server A). All of Server B's mail is routed through Server A. I can send to and from Server A fine. The other 2003 server (Server B) is located in a different active directory site. I can send from Server B to the EX2007 mailbox cluster but can't send to Server B from EX2007 cluster. The mail goes into the Unreachable Domain queue and the last error on the messages is "There is currently no route to the mailbox database". Any help with this issue would be greatly appreciate. Thanks.

Can you run ExBPA for all servers in your Exchange organization and see if you get any error? Later we may need to follow below article based on the problem you find... Troubleshooting Mail Flow from Exchange 2007 to Exchange 2003 When E-Mail Messages are Stuck in the Queue http://technet.microsoft.com/en-us/library/cc411329.aspx Amit Tank | MVP Exchange Server | MCITP: EMA | MCSA: M | http://ExchangeShare.WordPress.com

Thank you for the reply. I figured out what it was shortly after I posted. I had to allow permission inheritance to propogate on the server object in ESM. After that, everything worked properly. I followed the link below. http://technet.microsoft.com/en-us/library/aa998240.aspx