SMTP Diagnostics is a program that assists with troubleshooting problems that can occur with outgoing mail (SMTP). You can send a test message, with or without attachment(s), and view the protocol messages exchanged between your computer and the mail server. This information can help you analyze problems or can be passed on to technical support personnel.
SMTP Diagnostics is helpful when...
...configuring an SMTP mail server.
Have you ever spent time trying to configure an SMTP relay server and found that it took more time than it should? If you have ever configured an SMTP server for relaying messages then your answer is most likely "Yes". You make the settings and send a test message from your email client, but the message fails to reach its destination. Your email client might be able to tell you the message failed to send but it is unlikely it will tell you anything else such as the reason for the failure.
Here is where SMTP Diagnostics shines. Instead of sending the test message through your traditional email client, use SMTP Diagnostics to test the mail server and see the messages communicated between your computer and the mail server. There is no hidden detail. You will see every message as reported by the mail server including any error messages thus eliminating the guess work, which in turn saves you value time.
...troubleshooting email problems from a hotel network.
You are on a business trip and you are using the hotel's broadband network to send emails. Unfortunately the emails never seem to leave your Outbox. You check the error details from your email client but it only states the obvious, "Failed to send email". You are left with the time consuming process of guessing the source of the problem. SMTP Diagnostics to the rescue.
Launch SMTP Diagnostics, enter your email settings and click "Run Diagnostics" send a test message. Within seconds you will see a detailed report of the interaction between your computer and the mail server including the reason why emails are not sent out from your computer. Knowing the cause of the problem will help you fix the problem and get your email flowing once again.
...you cannot send email through your dial-up provider.
This problem drove me crazy for a period of time until I figured out that my dial-up provider requires all outgoing emails pass through their SMTP server. My dial-up provider never told me of this requirement. Because it was assumed the problem was the fault of my mail server, my dial-up provider's technical support staff would not offer assistance. After scouring the Internet for hours I finally learned that my dial-up provider required outgoing emails to pass through their SMTP mail server, which required changes to my email client's settings.
Had SMTP Diagnostics been available at that time I would have seen that the problem was caused by my dial-up provider. I could have reported the actual error message to their technical support staff and hopefully received the help I needed to get outbound emails flowing again.
