I receive a couple of these a day and not sure what they mean. Event Type:ErrorEvent Source:MSExchangeTransportEvent Category:SMTP Protocol Event ID:7004Date:5/7/2008Time:12:16:45 PMUser:N/AComputer:SERVER03Description:This is an SMTP protocol error log for virtual server ID 1, connection #6. The remote host "68.225.159.114", responded to the SMTP command "xexch50" with "500 5.5.1 Unrecognized command ". The full command sent was "XEXCH50 2548 2 ". This will probably cause the connection to fail. For more information, click http://www.microsoft.com/contentredirect.asp.

if the other server is not on your network yuo can ignore this. XEXCH50 is a SMTP verb that exchange servers issue to each other but to get it to work they must first authenticate to each other and this will not happen over internet. http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=917074&SiteID=17 http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=2312218&SiteID=17