We have just installed a new exchange server, and it isnt reciving external mails.
When we telnet to test the server, the first HELO is always denined:-
220 SV0002.<<MY SERVER NAME>> Microsoft ESMTP MAIL Service ready at Thu, 5 Jul 2012 10:19:57 +0100
500 5.3.3 Unrecognized command
250 SV0002.<<MY SERVER NAME>> Hello [<<MY SERVERS External IP<> ]
If I continue to test after it has accepted my second HELO the mail is delivered successfully, but if I send a mail from a normal client, I get nothing through, and no entries in the logs.