In my eventviewer I got a great amount of event ID errors 7010, MSEXchangeTransport. After reviewing the description I noticed all events came from the same IP-address. When looking up this IP, I found it to be a Unix/Linux host.
The full event ID is:
Event Type: Error
Event Source: MSExchangeTransport
Event Category: SMTP Protocol
Event ID: 7010
This is an SMTP protocol log for virtual server ID 1, connection #1126. The client at “192.168.0.2” sent a “mail” command, and the SMTP server responded with “501 5.5.4 Invalid Address “. The full command sent was “mail FROM: “. This will probably cause the connection to fail.
For more information, click http://www.microsoft.com/contentredirect.asp.
What this Unix/Linux host does is sending the HELO command with the FQDN name of the mailserver. Except it also has a trailing dot (.). For example :
When this is sent to an Exchange 2003 server it generates the following error:
501 5.5.4 Invalid Address
You are able to change Exchange and allow the trailing dot, but as this is not RFC compliant behaviour, I simply made sure the Unix/Linux host was configured to not send mail anymore.
If you want to change the behaviour of Exchange read the following knowledge base aricle : “501 5.5.4 Invalid Address” error message from a sending UNIX server