Hi,We have been using Exchange 2003 running on Server 2003 fine, until the other day. Emails are leaving the Server and when you run the tracker it appears to have gone, however they never arrive at there destination.The strange thing we never get an email stating it's failed, so they must be queued somewhere.Also we receive emails with out problemsSo far we have checkedBlacklistsRemoved AV from serverCan anyone help with more suggestions on what to check.ThanksPeter

How is yourExchangesetup? i.e. - what is your front end/backend setup, do you forward mail to a smart host etc...

Dear customer: 1. Is the recipient who received the e-mail external user or internal user? 2. How many Exchange servers do you have in your organization? 3. Tell me the complete routing topology of mail flow. Such as how many routing group, SMTP connector and etc. 4. Run Nslookup to check for DNS records of the domain Using NSlookup.exe http://support.microsoft.com/default.aspx?scid=kb;EN-US;200525 5. Can the customer Telnet to the domain from the Exchange server? Can the Microsoft engineer Telnet from their workstation to the domain? 153119 XFOR: Telnet to Port 25 to Test SMTP Communication http://support.microsoft.com/default.aspx?scid=kb;EN-US;153119 6. Take a Network Monitor trace on the server where the messages are queuing, force a connection on the queue, wait for retry and then stop the trace. 148942 How to capture network traffic with Network Monitor http://support.microsoft.com/default.aspx?scid=kb;EN-US;148942 7. Run Exchange Troubleshooting Analyzer (ExTRA) and select the Mail Flow Troubleshooter to troubleshoot Mailflow and transport-related problems. http://www.microsoft.com/downloads/details.aspx?familyid=4BDC1D6B-DE34-4F1C-AEBA-FED1256CAF9A&displaylang=en Hope it helps. If anything is unclear, please feel free to let me know. Rock Wang - MSFT