I am seeing the following being logged in the Application log of the event viewer many times daily;
Event Type: Error
Event Source: MSExchangeTransport
Event Category: SMTP Protocol
Event ID: 7010
Time: 12:25:20 PM
This is an SMTP protocol log for virtual server ID 1, connection #129. The client at "*.*.*.*" sent a "ehlo" command, and the SMTP server responded with "501 5.5.4 Invalid Address ". The full command sent was "ehlo xxxx.xxxxxxx.xx.*.*.*.*/24
This will probably cause the connection to fail.
For more information, click http://www.microsoft.com/contentredirect.asp
I am not an expert on Exchange but I 'think' this is not actually a problem, in fact that our Exchange is correctly not allowing relay as the client is not authenticating.
Can someone confirm?