Topic Last Modified: 2006-08-18

The Microsoft® Exchange Server Analyzer Tool transmits the EHLO Extended Simple Mail Transfer Protocol (ESMTP) command verb to port 25 of a remote server and analyzes the response to determine whether the remote server supports the BDAT ESMTP verb.

If the Exchange Server Analyzer receives a response with a string that indicates a non-retrievable error from the remote server, the Exchange Server Analyzer displays an error.

Exchange Server 2003 uses Exchange-specific extended SMTP verbs to communicate with other servers that are running Exchange Server in the organization. It is more efficient to communicate with Exchange-specific extended SMTP verbs than by using standard SMTP. If support for the ESMTP command set is disabled, Exchange Server performance may be hindered.

This error indicates that the remote server does not support the ESMTP BDAT command verb. The error does not indicate that the remote server is or is not an Exchange server. In either instance, messages that require the BDAT extension are not routed.

To address this issue, check the contents of the SMTP queues for messages that require the BDAT extension.

For more information about how to remove or restore the default support for these verbs, see Microsoft Knowledge Base article 257569 "How to turn off ESMTP verbs in Exchange 2000 Server and in Exchange Server 2003" (

For more information about how Exchange Server uses the ESMTP command verbs, see "How to Load Exchange SMTP Properly" in the Exchange Server Transport and Routing Guide (