Hi, I’m experiencing a problem with Eset Mail security (on SBS 2003 R2) blocking incoming mail from a particular sender. So far the only way I have found to prevent this is to disable Mail Security, which is obviously far from ideal. ESET Mail Security (4.2.10016.0) for Microsoft Exchange Server Symptoms: Email from email@example.com is not received by the mail store when Mail Security is enabled. Email from other users at the same domain (domain.com.au) is received. Email can be sent to firstname.lastname@example.org and is received. Cause: The Mail Security Transport Agent appears to be responsible. If I enable the transport agent and set the Transport Agent Options to send SMTP reject response, the SMTP reject response is received by the sender (email@example.com). Attempted Resolutions: Created a rule to take No Action for all emails from *@domain.com.au I need to be able to ensure legitimate email is delivered to the store and not rejected by the transport agent.