I am having difficulty sending e-mails to a specific domain. In my Exchange 2003 System Manager, there is an error that says AN SMTP ERROR PROTOCOL ERROR OCCURED. This only happens when sending to an e-mail address that has an @shaw.ca domain. I have tried restarting the smtp service, the virtual server as well as the exchange server itself. I have a second exchange server connected to the same domain and it can send the messages to these addresses. Any ideas? Thanks Paul Hawman

IHi, 1. Please follow the below article to test the Mail Connection How to use Telnet to test an Internet Mail Connection http://support.microsoft.com/kb/196748 2. Check MX and PTR record for your domain name. --- Nslookup --- set type=mx --- {domain name} http://www.dnsstuff.com/ 3. Check whether Host (A) record exists for their domain. 4. Check whether you domain name has SPF records. http://www.kitterman.com/spf/validate.html http://www.openspf.org/ 5. Check whether your server has been listed in the blacklist. http://www.mxtoolbox.com/blacklists.aspx?AG=MSN 6. Please try to disable the Recipient filtering to see whether it will work. 7. Besides, please run regedit from a command prompt and disabled the virus scan key,Registry Path : HKLM\System\CCS\Services\MsExchangeIS\VirusScan -- Enabled was set to 1,please change it to 0. If it is not the case, please post the detail error information here for further troubleshooting. Best regards, Xiu