SMTPDIAG is an utility from Microsoft that is a diagnostic tool to determine if Simple Mail Transfer Protocol (SMTP) and Domain Name System (DNS) are configured correctly to deliver mail to an external e-mail address. The application can be downloaded at:
The syntax for the application is:
SMTPDIAG "sender address" "recipient address" [-d target DNS] [/v]
Below is an example of the –d switch to specify a DNS server to use, as well as the /v switch to include more details.
The following error may be returned when the server is not an Exchange server and is not a member of an Active Directory domain.