Problem and background : 1. the two Exchange 2003 Standard servers are located in different subnets 2. the two subnets belong to same domain (our network is single domain structure) 3. the two servers are linked through routers and firewalls at each end 3. We are able to manage the two email servers through System Manager 4. emails sent to each other stayed at Internet Mail SMTP connectors at each end of the server 5. the emails eventually have been removed from the SMTP connector after couple of tries for resending All are welcome.

Well the firewall is the thing that jumps out at me. Is this blocking traffic? What queue is the message stuck in? Are these in different physical sites? do you have routing groups setup?

Thanks Mike. It was our thoughts as well that the firewalls played the role for the problem but we closely checked the setings and make sure firewalls allow all of this kind tracfic through. The tricky thing is that we are able to manage the remote site of the exchange server by using System Manager and the monitor tools in the System Manager also show that the remote email server is up and running. We also tested using Telnet and found that the response message from remote site was scrambled. We use Cisco firewalls and routers between these two sites (Atlanta and Sydney) with virtual VPN The email stuck at SMPT connector between the routing groups

Hi, An SMTP connector can be used to connect routing groups, but this is not recommended. SMTP connectors are designed for external message delivery. Please use routing group connector which provide the best connection between routing groups. See the following article for more information about routing group and routing group connector: Exchange Server 2003 Message Routing Topology http://technet.microsoft.com/en-us/library/aa996358(EXCHG.65).aspx Regarding how to create a routing group connector: XADM: How to Configure a Routing Group Connector http://support.microsoft.com/kb/267992 If the issue persists, please check your queue to see if any message hang there. How to use Queue Viewer to troubleshoot mail flow issues in Exchange Server 2003 http://support.microsoft.com/kb/823489/en-us Hope this helps. Thanks, Elvis

Hi Elvis, Thanks for pointing out the SMPT connector issue, we did use the routing group connector not "Internet Mail SMPT connector". the "SMPT connector" mentioned in my question is actually a remote bridgehead's virtual server "Default SMPT Virtual Server". The message stuck in the queuesis at "Default SMPT Virtual Server" with Name "Message waiting to be routed" Sorry for any confusing caused. Hong

Hi, The queue "Message waiting to be routed" holds messages until their next-destination server is determined. Have your check your routing group connector settings according to this article? If all is well, please increase diagnostic logging for the MSExchangeTransport service for the Routing category component to gather additional information, then check event log and paste related errors here for our further discussion. 1. Click Start, point to Programs, point to Microsoft Exchange, and then click System Manager. 2. Expand Servers, right-click Your_ Server_Name (where Your_ Server_Name is the name of your Exchange Server computer), and then click Properties. 3. Click the Diagnostics Logging tab, and then click MSExchangeTransport. 4. In the Categories section, click Routing category. 5. In the Logging Level area, click to choose maximum. 6. Reproduce the issue and check application log. Thanks, Elvis

Hi all, The issue has been solved by removingan entry " Fixup protocal SMTP 25" at Cisco PIX Firewalls on both sides. Thanks all for your helps.

Thank you for sharing with us!

Interesting. I have experienced this issue as well. Apparently the PIX reduces the traffic from EHLO to HELO, breaking Exchange to Exchange communication. You'll also notice it puts ******** where the normal greeting would go...